heat BMW 5 SERIES 1990 E34 User Guide

Flushing
7Once the system is completely drained,
flush the radiator with fresh water from a
garden hose until the water runs clear at the
drain or bottom hose. If the radiator is
severely corroded, damaged or leaking, it
should be removed (see Chapter 3) and taken
to a radiator repair specialist.
8Flushing in this way will remove sediments
from the radiator, but will not remove rust and
scale from the engine and cooling tube
surfaces. These deposits can be removed by
using a chemical cleaner. Follow the
procedure outlined in the cleaner
manufacturer’s instructions. Remove the
cylinder block drain plug before flushing the
engine.
9On models so equipped, remove the
overflow hose from the coolant recovery
reservoir. Drain the reservoir and flush it with
clean water, then reconnect the hose.
Refilling
10Tighten the radiator drain plug, or
reconnect the radiator bottom hose. Refit and
tighten the cylinder block drain plug.
Four-cylinder engines
11Slowly add new coolant (a 40%/60%
mixture of antifreeze to water) to the radiator
until it is full. Add coolant to the reservoir up
to the lower mark.
12Leave the radiator cap off, and run the
engine in a well-ventilated area until the
thermostat opens (coolant will begin flowing
through the radiator, and the upper radiator
hose will become hot).
13Turn the engine off, and let it cool. Add
more coolant mixture to bring the coolant
level back up to the lip on the radiator filler
neck. On the M40 engine, unscrew the bleed
screw from the top of the radiator, and add
coolant until it comes out of the bleed screw
hole. Refit and tighten the bleed screw.
14Squeeze the upper radiator hose to expel
air, then add more coolant mixture if
necessary. Refit the radiator cap.
15Start the engine, allow it to reach normal
operating temperature, and check for leaks.
Six-cylinder engines
16Loosen the bleed screw in the thermostat
housing (see illustration)
17Fill the radiator with a 40%/60% solution
of antifreeze and water until it comes out of
the bleed screw opening. Tighten the bleed
screw.
18Refit the radiator cap, and run the engine
until the thermostat opens (the upper radiator
hose will become hot). Slowly loosen the
bleed screw until no bubbles emerge, then
tighten the screw.
19Repeat the procedure until the air is bled
from the system.
30 Fuel filter renewal
1
Warning: Fuel is extremely
flammable, so take extra
precautions when you work on
any part of the fuel system. Don’t
smoke, or allow open flames or bare light
bulbs, near the work area. Don’t work in a
garage where a natural gas-type appliance
(such as a water heater or clothes dryer)
with a pilot light is present. If you spill any
fuel on your skin, rinse it off immediately
with soap and water. When you perform
any kind of work on the fuel system, wear
safety glasses, and have a fire
extinguisher on hand.
1On fuel injection engines, depressurise the
fuel system (see Chapter 4).
2The fuel filter is located in the engine
compartment on the bulkhead, or under the
vehicle adjacent to the fuel tank.
3Because on some models the filter is
located adjacent to the starter motor, fuel
could leak onto the electrical connections. For
safety reasons, therefore, disconnect the
battery negative cable before beginning work.
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you have
the correct activation code
before disconnecting the battery.Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
4Place a pan or rags under the fuel filter to
catch any spilled fuel. If suitable hose clamps
are available, clamp the inlet and outlet hoses.
5 Detach the hoses and remove the bracket
screws/nuts, then remove the filter and where
applicable the bracket assembly (see
illustration).
6Detach the filter from the bracket.
7Refitting is the reverse of removal. Be sure
the arrow on the filter points in the direction of
fuel flow.
31 Manual transmission
lubricant change
1
1Tools necessary for this job include axle
stands to support the vehicle in a raised
position, an Allen key to remove the drain
plug, a drain pan, newspapers and clean rags.
The correct amount of the specified lubricant
should also be available (see “Lubricants and
fluids”at the start of this Chapter).
2The lubricant should be drained when it is
hot (ie immediately after the vehicle has been
driven); this will remove any contaminants
better than if the lubricant were cold. Because
1•25
30.5 To renew the fuel filter, disconnect
the hoses (A), then unscrew the nut (B) and
detach the filter from the bracket (fuel
injection type shown)29.16 The bleed screw (arrowed) is
located on the thermostat housing (six-
cylinder models)29.4 Radiator drain plug location
(arrowed) - not fitted to all models
31.5 Use an Allen key to remove the drain
plug (arrowed) from the bottom of the
transmission
1
Every 24 000 miles

8 Timing chain and
sprockets- removal,
inspection and refitting
5
Note:This procedure applies to M10 and M30
engines.
Caution: Once the engine is set
at TDC, do not rotate the
camshaft or crankshaft until the
timing chain is reinstalled. If the
crankshaft or camshaft is rotated with the
timing chain removed, the valves could hit
the pistons, causing expensive internal
engine damage.
Removal
1Position the No 1 cylinder at Top Dead
Centre (TDC) on the compression stroke (see
Section 3).
2Remove the valve cover (see Section 4).
Double-check that the No 1 cylinder is at TDC
on the compression stroke by making sure the
No 1 cylinder rocker arms are loose (not
compressing their valve springs).
3Remove the upper timing chain cover (see
Section 7). Note the location of the camshaft
timing marks, which should now be aligned.
On four-cylinder (M10) engines, there’s
usually a stamped line on the camshaft flange
that aligns with a cast mark on the top of the
cylinder head; also, the camshaft sprocket
dowel pin hole will be at its lowest point. On
six-cylinder (M30) engines, a line drawn
through two of the camshaft sprocket bolts
opposite each other would be exactly vertical,
while a line drawn through the other two bolts
would be horizontal. Additionally, the locating
pin should be in the lower left corner (between
the 7 and 8 o’clock positions). Be sure you’ve
identified the correct camshaft TDC position
before dismantling, because correct valve
timing depends on you aligning them exactly
on reassembly. Note:As the engine is
mounted in the engine compartment at anangle, all references to horizontal and vertical
whilst timing the camshafts are in relation to
the crankshaft, and not the ground.
4Hold the crankshaft stationary with a socket
and ratchet on the vibration damper centre bolt,
then loosen (but don’t unscrew completely) the
four bolts attaching the camshaft sprocket to
the camshaft. Be very careful not to rotate the
camshaft or crankshaft. Note:Some earlier
models may have locking tabs for the camshaft
sprocket bolts. Bend the tabs down before
loosening the bolts. The tabs are no longer
available from the manufacturer, and do not
have to be used on refitting.
5Remove the lower timing chain cover (see
Section 7).
6Unscrew and remove the four camshaft
sprocket bolts, then disengage the chain from
the crankshaft sprocket and carefully remove
the chain and camshaft sprocket from the
engine. It may be necessary to gently prise
the camshaft sprocket loose from the
camshaft with a screwdriver.
Inspection
Timing sprockets
7Examine the teeth on both the crankshaft
sprocket and the camshaft sprocket for wear.
Each tooth forms an inverted V. If worn, the
side of each tooth under tension will be
slightly concave in shape when compared
with the other side of the tooth (i.e. one side of
the inverted V will be concave when
compared with the other, giving the teeth a
hooked appearance). If the teeth appear to be
worn, the sprockets must be renewed. Note:
The crankshaft sprocket is a press fit on the
crankshaft, and can be removed with a jaw-
type puller after the Woodruff key and oil
pump are removed (see Section 14). However,
BMW recommends the new sprocket be
pressed onto the crankshaft after being
heated to 80°C (175°F) on the M10 engine, or
to 200°C(390°F) on the M30 engine. For this
reason, if the crankshaft sprocket requires
renewal, we recommend removing the
crankshaft (see Part B of this Chapter) and
taking it to an engineering works to have the
old sprocket pressed off and a new one
pressed on.
Timing chain
8The chain should be renewed if the
sprockets are worn or if the chain is loose
(indicated by excessive noise in operation).
It’s a good idea to renew the chain anyway if
the engine is stripped down for overhaul. The
rollers on a very badly worn chain may be
slightly grooved. To avoid future problems, if
there’s any doubt at all about the chain’s
condition, renew it.
Chain rail and tensioner
9Inspect the chain guide rail and tensioner
rail for deep grooves caused by chain contact.
Renew them if they are excessively worn. The
rails can be renewed after removing the
circlips with a pointed tool or needle-nose
pliers (see illustration).10Shake the tensioner plunger, and listen for
a rattling sound from the check ball. If you
can’t hear the ball rattling, renew the plunger.
11To further check the tensioner plunger,
blow through it first from the closed end, then
from the slotted (guide) end. No air should
flow through the plunger when you blow
through the closed end, and air should flow
through it freely when you blow through the
slotted end. If the tensioner fails either test,
renew it.
Refitting
12Refit the tensioner rail and chain guide
rail, if removed.
13Temporarily refit the lower timing chain
cover and vibration damper, so you can check
the crankshaft timing marks. Once you’ve
verified the TDC marks are aligned, remove
the damper and cover.
14Loop the timing chain over the crankshaft
sprocket, then loop it over the camshaft
sprocket and, guiding the chain between the
chain guide and tensioner rail, refit the
camshaft sprocket on the camshaft. Make
sure the camshaft timing marks are aligned.
15The remainder of refitting is the reverse of
removal. Be sure to tighten the fasteners to
the correct torques (see this Chapter’s Speci-
fications).
9 Timing belt covers-
removal and refitting
2
Note:This procedure applies to M20 and M40
engines.
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you
have the correct activation code
before disconnecting the battery.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
1Disconnect the battery negative cable.
2Remove the fan clutch and fan shroud (see
Chapter 3).
3On the M20 engine, remove the radiator
(see Chapter 3).
4Remove the fan drivebelt pulley.
2A•8 In-car engine repair procedures
9.6a Unbolt the distributor cap
(M40 engine) . . .
8.9 To remove the tensioner or chain guide
rail, remove the circlips with a pointed tool
or needle-nose pliers - the circlips tend to
fly off when they’re released, so make sure
you catch them or they’ll get lost (or,
worse, wind up in the engine!)

22Using a scraper, remove all traces of old
gasket material from the sealing surfaces of
the covers and engine block.
Caution: Be very careful not to
scratch or gouge the delicate
aluminium surfaces. Also, do not
damage the sump gasket, and
keep it clean. Gasket removal solvents are
available at motor factors, and may
prove helpful. After all gasket material has
been removed, the gasket surfaces
can be degreased by wiping them
with a rag dampened with a suitable
solvent.
23Support the cover on two blocks of wood,
and drive out the seals from behind with a
hammer and screwdriver. Be very careful not
to damage the seal bores in the process.
24Coat the outside diameters and lips of the
new seals with multi-purpose grease, and
drive the seals into the cover with a hammer
and a socket slightly smaller in diameter than
the outside diameter of the seal.
25Apply a film of RTV-type gasket sealant to
the surface of the sump gasket that mates
with the front cover. Apply extra beads of RTV
sealant to the edges where the gasket meets
the engine block. Note:If the sump gasket is
damaged, instead of fitting a whole new
gasket, you might try trimming the front
portion of the gasket off at the point where it
meets the engine block, then trim off the front
portion of a new sump gasket so it’s exactly
the same size. Cover the exposed inside area
of the sump with a rag, then clean all traces of
old gasket material off the area where the
gasket was removed. Attach the new gasket
piece to the sump with contact-cement-type
gasket adhesive, then apply RTV-type sealant
as described at the beginning of this
paragraph.
26Coat both sides of the new gasket with
RTV-type gasket sealant, then attach the front
cover to the front of the engine, carefully
working the seals over the crankshaft and
intermediate shaft. Refit the bolts and tighten
them evenly to the torque listed in this
Chapter’s Specifications. Work from bolt-to-
bolt in a criss-cross pattern, to be sure they’re
tightened evenly.Note 1:Tighten the front
cover-to-block bolts first, then tighten the
sump-to-cover bolts. Note 2:After applying
RTV-type sealant, reassembly must be
completed in about 10 minutes so the RTV
won’t prematurely harden.
27The remainder of refitting is the reverse of
removal.
Crankshaft front seal (M40 engines)
28Remove the timing belt and crankshaft
sprocket (see Section 10).
29Remove the Woodruff key from the
groove in the end of the crankshaft.
30Note the fitted position of the oil seal, then
prise it out from the front cover using a
screwdriver, but take care not to damage the
bore of the cover or the surface of thecrankshaft. If the seal is tight, drill two small
holes in the metal end of the seal, and use two
self-tapping screws to pull out the seal. Make
sure all remains of swarf are removed.
31Coat the outside diameter and lip of the
new seal with multi-purpose grease, then
drive it into the cover with a hammer and a
socket slightly smaller in diameter than the
outside diameter of the seal. Make sure the
seal enters squarely.
32The remainder of refitting is the reverse of
removal. Note that it is recommended that the
timing belt be renewed - see Section 10.
12 Cylinder head-
removal and refitting
5
Removal
1Relieve the fuel pressure on all fuel injection
engines (see Chapter 4).
2Disconnect the negative cable from the
battery. Where the battery is located in the
engine compartment, the battery may be
removed completely (see Chapter 5).
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you
have the correct activation code
before disconnecting the battery.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
3Remove the air cleaner assembly (see
Chapter 4).
4Disconnect the wiring from the distributor
(mark all wiring for position first, if necessary),
and the HT lead from the coil (see Chapter 5).
5Disconnect the lead from the coolant
temperature sender unit (see Chapter 3).
6Disconnect the fuel lines from the fuel rail or
carburettor as applicable (see Chapter 4).
7Drain the cooling system (see Chapter 3).
8Clearly label then disconnect all other
hoses from the throttle body, intake manifold,
carburettor and cylinder head, as applicable.
9Disconnect the throttle cable from the
throttle linkage or carburettor (see Chapter 4).
10Disconnect the exhaust manifold from the
cylinder head (see Section 6). Depending on
the engine type, It may not be necessary to
disconnect the manifold from the exhaust
pipe; however, on right-hand-drive models,
the steering column intermediate shaft may
not allow the manifold to clear the studs on
the cylinder head.
11Remove or disconnect any remaining
hoses or lines from the intake manifold,
including the ignition advance vacuum line(s),
and the coolant and heater hoses.
12On early carburettor models, disconnect
the wiring from the alternator and starter
motor.13Remove the intake manifold (see Sec-
tion 5). Do not dismantle or remove any fuel
injection system components unless it is
absolutely necessary.
14Remove the fan drivebelt and fan (see
Chapter 3).
15Remove the valve cover and gasket (see
Section 4). Remove the semi-circular rubber
seal from the front of the cylinder head, where
this is not incorporated in the valve cover
gasket.
16Set No 1 piston at Top Dead Centre on
the compression stroke (see Section 3).
17Remove the timing chain or belt (see
Section 8 or 10). Note:If you want to save
time by not removing and refitting the timing
belt or chain and re-timing the engine, you can
unfasten the camshaft sprocket and suspend
it out of the way - with the belt or chain still
attached - by a piece of rope. Be sure the
rope keeps firm tension on the belt or chain,
so it won’t become disengaged from any of
the sprockets.
18Loosen the cylinder head bolts a quarter-
turn at a time each, in the reverse of the
tightening sequence shown (see illustrations
12.30a, 12.30b, 12.30c or 12.30d). Do
notdismantle or remove the rocker arm
assembly at this time on M10, M20 and M30
engines.
19Remove the cylinder head by lifting it
straight up and off the engine block. Do not
prise between the cylinder head and the
engine block, as damage to the gasket sealing
surfaces may result. Instead, use a blunt bar
positioned in an intake port to gently prise the
head loose.
20Remove any remaining external
components from the head to allow for
thorough cleaning and inspection. See
Chapter 2B for cylinder head servicing
procedures. On the M40 engine, remove the
rubber O-ring from the groove in the top of the
oil pump/front end cover housing.
Refitting
21The mating surfaces of the cylinder head
and block must be perfectly clean when the
head is refitted.
22Use a gasket scraper to remove all traces
of carbon and old gasket material, then clean
the mating surfaces with a suitable solvent. If
there’s oil on the mating surfaces when the
head is refitted, the gasket may not seal
correctly, and leaks could develop. When
working on the block, stuff the cylinders with
clean rags to keep out debris. Use a vacuum
cleaner to remove material that falls into the
cylinders.
23Check the block and head mating
surfaces for nicks, deep scratches and other
damage. If the damage is slight, it can be
removed with a file; if it’s excessive,
machining may be the only alternative.
24Use a tap of the correct size to chase the
threads in the head bolt holes, then clean the
holes with compressed air - make sure that
In-car engine repair procedures 2A•13
2A

detach them. Pieces of masking tape with
numbers or letters written on them work well
(see illustration).
6Label and detach all coolant hoses from the
engine (see Chapter 3).
7Remove the cooling fan, shroud and
radiator (see Chapter 3). Note:On the M40
engine, it is only necessary to remove the
cooling fan and shroud; however, prevent
damage to the radiator by covering it with a
piece of wood or cardboard.
8Remove the drivebelts (see Chapter 1).
9Disconnect the fuel lines from the fuel rail
(see Chapter 4).
Warning: Fuel is extremely
flammable, so take extra
precautions when you work on
any part of the fuel system. Don’t
smoke, or allow open flames or bare light
bulbs, near the work area, and don’t work
in a garage where a natural gas-type
appliance (such as a water heater or
clothes dryer) with a pilot light is present.
If you spill any fuel on your skin, rinse it off
immediately with soap and water. When
you perform any kind of work on the fuel
system, wear safety glasses, and have a
fire extinguisher on hand.
10Disconnect the accelerator cable (see
Chapter 4) and kickdown linkage/speed
control cable (see Chapter 7B), if applicable,
from the engine.
11Where fitted, unbolt the power steering
pump (see Chapter 10). Leave the lines/hoses
attached, and make sure the pump is kept in
an upright position in the engine compartment
(use wire or rope to restrain it out of the way).
12On air-conditioned models, unbolt the
compressor (see Chapter 3) and set it aside,
or tie it up out of the way. Do not disconnect
the hoses.
13Drain the engine oil (see Chapter 1) and
remove the filter. Remove the engine splash
guard from under the engine.
14Remove the starter motor (see Chapter 5).15Remove the alternator (see Chapter 5).
This is not essential on all models, but it is a
good idea in any case to avoid accidental
damage.
16Unbolt the exhaust system from the
engine (see Chapter 4).
17If you’re working on a vehicle with an
automatic transmission, remove the torque
converter-to-driveplate fasteners (see
Chapter 7B). On the M40 engine, unbolt the
automatic transmission fluid coolant pipes
from the sump.
18Support the transmission with a jack.
Position a block of wood between them, to
prevent damage to the transmission. Special
transmission jacks with safety chains are
available - use one if possible.
19Attach an engine sling or a length of chain
to the lifting brackets on the engine. If the
brackets have been removed, the chain can
be bolted directly to the intake manifold studs,
but place a flat washer between the chain and
the nut, and tighten the nut all the way up to
the chain, to avoid the possibility of the studs
bending.
20Roll the hoist into position and connect
the sling to it. Take up the slack in the sling or
chain, but don’t lift the engine.
Warning: DO NOT place any part
of your body under the engine
when it’s supported only by a
hoist or other lifting device.
21On M10, M20 and M30 engines, remove
the transmission rear crossmember, and
slightly lower the rear of the transmission.
22Remove the transmission-to-engine block
bolts using a Torx socket. Note:The bolts
holding the bellhousing to the engine block
will require a swivel at the socket, and a very
long extension going back towards the
transmission.
23Remove the engine mounting-to-frame
bracket nuts. On the M40 engine, unbolt the
dampers from the mountings.
24Recheck to be sure nothing is still
connecting the engine to the transmission or
vehicle. Disconnect anything still remaining.
25Raise the engine slightly. Carefully work it
forwards to separate it from the transmission.
If you’re working on a vehicle with an
automatic transmission, you may find the
torque converter comes forward with theengine. If it stays with the transmission, leave
it, but you may find it easier to let it come
forward until it can be grasped easier and be
pulled from the crankshaft. Note:When
refitting the torque converter to the
transmission before the engine is refitted, be
sure to renew the transmission front pump
seal, which will probably be damaged when
the converter comes out with the engine.
Either method is acceptable, but be prepared
for some fluid to leak from the torque
converter if it comes out of the transmission. If
you’re working on a vehicle with a manual
transmission, draw the engine forwards until
the input shaft is completely disengaged from
the clutch. Slowly raise the engine out of the
engine compartment. Check carefully to make
sure everything is disconnected.
26Remove the flywheel/driveplate (and
where applicable, the engine rear plate), and
mount the engine on an engine stand (see
illustration). Do not turn the M40 engine
upside-down (see Cautionin Section 4).
Refitting
27Check the engine and transmission
mountings. If they’re worn or damaged, renew
them.
28Refit the flywheel or driveplate (see
Chapter 2A). If you’re working on a manual
transmission vehicle, refit the clutch and
pressure plate (see Chapter 7A). Now is a
good time to fit a new clutch.
29If the torque converter came out with the
engine during removal, carefully refit the
converter into the transmission before the
engine is lowered into the vehicle.
30Carefully lower the engine into the engine
compartment - make sure the engine
mountings line up.
31If you’re working on an automatic
transmission vehicle, guide the torque
converter onto the crankshaft following the
procedure outlined in Chapter 7B.
32If you’re working on a manual
transmission vehicle, apply a dab of high-
melting-point grease to the input shaft, and
guide it into the clutch and crankshaft pilot
bearing until the bellhousing is flush with the
engine block.. Do not allow the weight of the
engine to hang on the input shaft.
33Refit the transmission-to-engine bolts,
and tighten them securely.
Caution: DO NOT use the bolts to
force the transmission and
engine together.
34Refit the remaining components in the
reverse order of removal.
35Add coolant, oil, power steering and
transmission fluid as needed.
2B•6 General engine overhaul procedures
5.26 Removing the engine rear plate -
M40 engine5.5 Label each wire before unplugging the
connector
If there’s any possibility of
confusion, make a sketch of
the engine compartment and
clearly label the lines, hoses
and wires.
It may be necessary to rock
the engine slightly, or to turn
the crankshaft, to allow the
input shaft splines to mate
with the clutch plate

24Repeat the procedure for the remaining
valves. Remember to keep all the parts for
each valve together, so they can be refitted in
the same locations.
25Once the valves and related components
have been removed and stored in an
organised manner, the head should be
thoroughly cleaned and inspected. If a
complete engine overhaul is being done,
finish the engine dismantling procedures
before beginning the cylinder head cleaning
and inspection process.
9 Cylinder head and
components-
cleaning and inspection
4
1Thorough cleaning of the cylinder head(s)
and related valve train components, followed
by a detailed inspection, will enable you to
decide how much valve service work must be
done during the engine overhaul. Note: If the
engine was severely overheated, the cylinder
head is probably warped (see paragraph 10).
Cleaning
2Scrape all traces of old gasket material and
sealing compound off the cylinder head,
intake manifold and exhaust manifold sealing
surfaces. Be very careful not to gouge the
cylinder head. Special gasket removal
solvents are available at motor factors.
3Remove all built-up scale from the coolant
passages.
4Run a stiff brush through the various holes
to remove deposits that may have formed in
them.
5Run an appropriate-size tap into each of the
threaded holes, to remove corrosion and
thread sealant that may be present. If
compressed air is available, use it to clear the
holes of debris produced by this operation.
Warning: Wear eye protection
when using compressed air!
6Clean the cylinder head with solvent, and
dry it thoroughly. Compressed air will speed
the drying process, and ensure that all holesand recessed areas are clean. Note:
Decarbonising chemicals are available, and
may prove very useful when cleaning cylinder
heads and valve train components. They are
very caustic, however, and should be used
with caution. Be sure to follow the instructions
on the container.
7Clean all the rocker shafts/arms/followers,
springs, valve springs, spring seats, keepers
and retainers with solvent, and dry them
thoroughly. Clean the components from one
valve at a time, to avoid mixing up the parts.
Caution: DO NOT clean the
hydraulic tappets of the M40
engine; leave them completely
immersed in oil.
8Scrape off any heavy deposits that may
have formed on the valves, then use a
motorised wire brush to remove deposits from
the valve heads and stems. Again, make sure
the valves don’t get mixed up.
Inspection
Note: Be sure to perform all of the following
inspection procedures before concluding that
machine shop work is required. Make a list of
the items that need attention.
Cylinder head
9Inspect the head very carefully for cracks,
evidence of coolant leakage, and other
damage. If cracks are found, check with an
machine shop concerning repair. If repair isn’t
possible, a new cylinder head should be
obtained.
10Using a straightedge and feeler gauge,
check the head gasket mating surface for
warpage (see illustration). If the warpage
exceeds the limit listed in this Chapter’s
Specifications, it may be possible to have it
resurfaced at a machine shop, providing the
head is not reduced to less than the specified
minimum thickness.
11Examine the valve seats in each of the
combustion chambers. If they’re badly pitted,
cracked or burned, the head will require
servicing that’s beyond the scope of the home
mechanic.12Check the valve stem-to-guide clearance
by measuring the lateral movement of the
valve stem with a dial indicator (see
illustration). The valve must be in the guide
and approximately 2.0 mm off the seat. The
total valve stem movement indicated by the
gauge needle must be divided by two, to
obtain the actual clearance. After this is done,
if there’s still some doubt regarding the
condition of the valve guides, they should be
checked by a machine shop (the cost should
be minimal).
Valves
13Carefully inspect each valve face for
uneven wear, deformation, cracks, pits and
burned areas (see illustration). Check the
valve stem for scuffing and the neck for
cracks. Rotate the valve, and check for any
obvious indication that it’s bent. Look for pits
and excessive wear on the end of the stem.
The presence of any of these conditions
indicates the need for valve service as
described in the next Section.
14Measure the margin width on each valve
(see illustration). Any valve with a margin
narrower than specified will have to be
replaced with a new one.
Valve components
15Check each valve spring for wear on the
ends. The tension of all springs should be
checked with a special fixture before deciding
2B•10 General engine overhaul procedures
9.14 The margin width on each valve must
be as specified (if no margin exists, the
valve cannot be reused)
9.13 Check for valve wear at the points
shown here
9.12 A dial indicator can be used to
determine the valve stem-to-guide
clearance (move the valve as indicated by
the arrows)
9.10 Check the cylinder head gasket
surface for warpage by trying to slip a
feeler gauge under the straightedge (see
this Chapter’s Specifications for the
maximum warpage allowed, and use a
feeler gauge of that thickness)
1 Valve tip
2 Collet groove
3 Stem (least-worn
area)4 Stem (most-worn
area)
5 Valve face
6 Margin

7Wipe the oil out of the cylinder, and repeat
the procedure for the remaining cylinders.
8After the honing job is complete, chamfer
the top edges of the cylinder bores with a
small file, so the rings won’t catch when the
pistons are refitted. Be very careful not to nick
the cylinder walls with the end of the file.
9The entire engine block must be washed
again very thoroughly with warm, soapy
water, to remove all traces of the abrasive grit
produced during the honing operation. Note:
The bores can be considered clean when a
lint-free white cloth - dampened with clean
engine oil - used to wipe them out doesn’t
pick up any more honing residue, which will
show up as grey areas on the cloth.Be sure to
run a brush through all oil holes and galleries,
and flush them with running water.
10After rinsing, dry the block, and apply a
coat of light rust-preventive oil to all machined
surfaces. Wrap the block in a plastic bag to
keep it clean, and set it aside until
reassembly.
18 Pistons/connecting rods-
inspection
3
1Before the inspection process can be
carried out, the piston/connecting rod
assemblies must be cleaned and the original
piston rings removed from the pistons.Note:
Always use new piston rings when the engine
is reassembled.
2Using a piston ring refitting tool, carefully
remove the rings from the pistons. Be careful
not to nick or gouge the pistons in the
process (see illustration).
3Scrape all traces of carbon from the top of
the piston. A hand-held wire brush or a piece
of fine emery cloth can be used once the
majority of the deposits have been scraped
away. Do not, under any circumstances, use a
wire brush mounted in a drill motor to remove
deposits from the pistons. The piston material
is soft, and may be damaged by the wire
brush.
4Use a piston ring groove cleaning tool to
remove carbon deposits from the ring
grooves. Be very careful to remove only thecarbon deposits - don’t remove any metal,
and do not nick or scratch the sides of the
ring grooves (see illustration).
5Once the deposits have been removed,
clean the piston/rod assemblies with solvent,
and dry them with compressed air (if
available). Make sure the oil return holes in the
back sides of the ring grooves are clear.
6If the pistons and cylinder walls aren’t
damaged or worn excessively, and if the
engine block is not rebored, new pistons
won’t be necessary. Normal piston wear
appears as even vertical wear on the piston
thrust surfaces (90° to the gudgeon pin bore),
and slight looseness of the top ring in its
groove. New piston rings, however, should
always be used when an engine is rebuilt.
7Carefully inspect each piston for cracks
around the skirt, at the pin bosses, and at the
ring lands.
8Look for scoring and scuffing on the thrust
faces of the skirt, holes in the piston crown,
and burned areas at the edge of the crown. If
the skirt is scored or scuffed, the engine may
have been suffering from overheating and/or
abnormal combustion, which caused
excessively high operating temperatures. The
cooling and lubrication systems should be
checked thoroughly. A hole in the piston crown
is an indication that abnormal combustion (pre-
ignition) was occurring. Burned areas at the
edge of the piston crown are usually evidence
of spark knock (detonation). If any of the aboveproblems exist, the causes must be corrected,
or the damage will occur again. The causes
may include intake air leaks, incorrect fuel/air
mixture, or incorrect ignition timing. On later
vehicles with high levels of exhaust emission
control, including catalytic converters, the
problem may be with the EGR (exhaust gas
recirculation) system, where applicable.
9Corrosion of the piston, in the form of small
pits, indicates that coolant is leaking into the
combustion chamber and/or the crankcase.
Again, the cause must be corrected or the
problem may persist in the rebuilt engine.
10Measure the piston ring side clearance by
laying a new piston ring in each ring groove
and slipping a feeler gauge in beside it(see
illustration). Check the clearance at three or
four locations around each groove. Be sure to
use the correct ring for each groove - they are
different. If the side clearance is greater than
the figure listed in this Chapter’s Specifi-
cations, new pistons will have to be used.
11Check the piston-to-bore clearance by
measuring the bore (see Section 16) and the
piston diameter. Make sure the pistons and
bores are correctly matched. Measure the
piston across the skirt, at 90° to, and in line
with, the gudgeon pin (see illustration). (Any
difference between these two measurements
indicates that the piston is no longer perfectly
round.) Subtract the piston diameter from the
bore diameter to obtain the clearance. If it’s
greater than specified, the block will have to
be rebored, and new pistons and rings fitted.
2B•16 General engine overhaul procedures
18.11 Measure the piston diameter at a
90-degree angle to the gudgeon pin, at the
same height as the gudgeon pin
18.10 Check the ring side clearance with a
feeler gauge at several points around the
groove18.4 The piston ring grooves can be
cleaned with a special tool, as shown
here18.2 Removing the compression rings with
a ring expander - note the mark (arrowed)
facing up
If a groove cleaning tool isn’t available,
a piece broken off the old ring will do
the job, but protect your hands - piston
rings can be sharp

3When examining the bearings, remove
them from the engine block, the main bearing
caps, the connecting rods and the rod caps,
and lay them out on a clean surface in the
same general position as their location in the
engine. This will enable you to match any
bearing problems with the corresponding
crankshaft journal.
4Dirt and other foreign particles get into the
engine in a variety of ways. It may be left in
the engine during assembly, or it may pass
through filters or the crankcase ventilation
(PCV) system. It may get into the oil, and from
there into the bearings. Metal chips from
machining operations and normal engine wear
are often present. Abrasives are sometimes
left in engine components after recondi-
tioning, especially when parts are not
thoroughly cleaned using the proper cleaning
methods. Whatever the source, these foreign
objects often end up embedded in the soft
bearing material, and are easily recognised.
Large particles will not embed in the bearing,
and will score or gouge the bearing and
journal. The best prevention for this cause of
bearing failure is to clean all parts thoroughly,
and to keep everything spotlessly-clean
during engine assembly. Frequent and regular
engine oil and filter changes are also
recommended.
5Lack of lubrication (or lubrication
breakdown) has a number of interrelated
causes. Excessive heat (which thins the oil),
overloading (which squeezes the oil from the
bearing face) and oil “leakage” or “throw off”
(from excessive bearing clearances, worn oil
pump, or high engine speeds) all contribute to
lubrication breakdown. Blocked oil passages,
which usually are the result of misaligned oil
holes in a bearing shell, will also oil-starve a
bearing and destroy it. When lack of
lubrication is the cause of bearing failure, the
bearing material is wiped or extruded from the
steel backing of the bearing. Temperatures
may increase to the point where the steel
backing turns blue from overheating.
6Driving habits can have a definite effect on
bearing life. Full-throttle, low-speed operation
(labouring the engine) puts very high loads onbearings, which tends to squeeze out the oil
film. These loads cause the bearings to flex,
which produces fine cracks in the bearing
face (fatigue failure). Eventually, the bearing
material will loosen in places, and tear away
from the steel backing. Short-trip driving
leads to corrosion of bearings, because
insufficient engine heat is produced to drive
off the condensation and corrosive gases.
These products collect in the engine oil,
forming acid and sludge. As the oil is carried
to the engine bearings, the acid attacks and
corrodes the bearing material.
7Incorrect bearing refitting during engine
assembly will lead to bearing failure as well.
Tight-fitting bearings leave insufficient bearing
oil clearance, and will result in oil starvation.
Dirt or foreign particles trapped behind a
bearing shell result in high spots on the
bearing, which will lead to failure.
21 Engine overhaul-
reassembly sequence
1Before beginning engine reassembly, make
sure you have all the necessary new parts,
gaskets and seals, as well as the following
items on hand:
Common hand tools
A torque wrench
Piston ring refitting tool
Piston ring compressor
Vibration damper refitting tool
Short lengths of rubber or plastic hose to fit
over connecting rod bolts (where
applicable)
Plastigage
Feeler gauges
A fine-tooth file
New engine oil
Engine assembly oil or molybdenum
disulphide (“moly”) grease
Gasket sealant
Thread-locking compound
2In order to save time and avoid problems,
engine reassembly should be done in the
following general order:Piston rings
Crankshaft and main bearings
Piston/connecting rod assemblies
Oil pump
Sump
Cylinder head assembly
Timing belt or chain and tensioner
assemblies
Water pump
Timing belt or chain covers
Intake and exhaust manifolds
Valve cover
Engine rear plate
Flywheel/driveplate
22 Piston rings- refitting
2
1Before fitting the new piston rings, the ring
end gaps must be checked. It’s assumed that
the piston ring side clearance has been
checked and verified (see Section 18).
2Lay out the piston/connecting rod
assemblies and the new ring sets, so that the
ring sets will be matched with the same piston
and cylinder during the end gap measurement
and engine assembly.
3Insert the top ring into the first cylinder, and
square it up with the cylinder walls by pushing
it in with the top of the piston (see illustration).
The ring should be near the bottom of the
cylinder, at the lower limit of ring travel.
4To measure the end gap, slip feeler gauges
between the ends of the ring until a gauge equal
to the gap width is found(see illustration). The
feeler gauge should slide between the ring ends
with a slight amount of drag. Compare the
measurement to this Chapter’s Specifications.
If the gap is larger or smaller than specified,
double-check to make sure you have the
correct rings before proceeding.
5If the gap is too small, it must be enlarged,
or the ring ends may come in contact with
each other during engine operation, which
can cause serious damage to the engine. The
end gap can be increased by filing the ring
ends very carefully with a fine file. Mount the
2B•18 General engine overhaul procedures
22.5 If the end gap is too small, clamp a
file in a vice, and file the ring ends (from
the outside in only) to enlarge the gap
slightly22.4 With the ring square in the cylinder,
measure the end gap with a feeler gauge22.3 When checking piston ring end gap,
the ring must be square in the cylinder
bore (this is done by pushing the ring down
with the top of a piston as shown)

3General
Coolant capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Thermostat rating
Opening temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80°C (176°F)
Fully open at . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100°C (212°F)
Cooling fan thermo-switch - switching temperatures
Low-speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91°C (196°F)
High-speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99°C (210°F)
Torque wrench settingsNm
Mechanical cooling fan clutch-to-water pump securing
nut (left-hand thread) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Mechanical cooling fan-to-clutch bolts . . . . . . . . . . . . . . . . . . . . . . . . . 10
Water pump bolts
Small bolts (M6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Large bolts (M8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Thermostat housing bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Chapter 3
Cooling, heating and air conditioning systems
Air conditioner receiver-drier - removal and refitting . . . . . . . . . . . . 16
Air conditioning blower motor (E28/”old-shape” 5-series
models) - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Air conditioning compressor - removal and refitting . . . . . . . . . . . . . 13
Air conditioning condenser - removal and refitting . . . . . . . . . . . . . . 15
Air conditioning system - precautions and maintenance . . . . . . . . . 12
Antifreeze - general information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Coolant level check . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Coolant temperature sender unit - check and renewal . . . . . . . . . . . 8
Cooling system check . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Cooling system servicing (draining, flushing and refilling)See Chapter 1Engine cooling fan(s) and clutch - check, removal and refitting . . . . 5
Evaporator matrix - removal and refitting . . . . . . . . . . . . . . . . . . . . . 17
General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Heater and air conditioner control assembly - removal and refitting 10
Heater and air conditioning blower motor - removal,testing and
refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Heater matrix - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . 11
Radiator - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Thermostat - check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Water pump - check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Water pump - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . 7
3•1
Easy,suitable for
novice with little
experienceFairly easy,suitable
for beginner with
some experienceFairly difficult,
suitable for competent
DIY mechanic
Difficult,suitable for
experienced DIY
mechanicVery difficult,
suitable for expert
DIY or professional
Degrees of difficulty
Specifications Contents
1 General information
Engine cooling system
All vehicles covered by this manual employ
a pressurised engine cooling system, with
thermostatically-controlled coolant circulation.
An impeller-type water pump mounted on
the front of the block pumps coolant through
the engine. The coolant flows around each
cylinder, and towards the rear of the engine.
Cast-in coolant passages direct coolantaround the intake and exhaust ports, near the
spark plug areas, and in close proximity to the
exhaust valve guides.
A wax-pellet-type thermostat is located in-
line in the bottom hose on M10 engines, in a
housing near the front of the engine on M20
and M30 engines, or behind an elbow under
the timing belt upper cover (on the front of the
cylinder head) on M40 engines. During warm-
up, the closed thermostat prevents coolant
from circulating through the radiator. As the
engine nears normal operating temperature,
the thermostat opens and allows hot coolant
to travel through the radiator, where it’s
cooled before returning to the engine.The pressure in the system raises the
boiling point of the coolant, and increases the
cooling efficiency of the radiator. The cooling
system is sealed by a pressure-type cap. If
the system pressure exceeds the cap
pressure relief value, the excess pressure in
the system forces the spring-loaded valve
inside the cap off its seat, and allows the
coolant to escape through the overflow tube.
The pressure cap on four-cylinder models is
on the top of the radiator; on six-cylinder models,
it’s on top of a translucent plastic expansion
tank. The cap pressure rating is moulded into the
top of the cap. The pressure rating is either
1.0 bar (14 psi) or 1.2 bars (17 psi).

Warning: Do not remove the
pressure cap from the radiator or
expansion tank until the engine
has cooled completely and
there’s no pressure remaining in the
cooling system. Removing the cap from a
hot engine risks personal injury by
scalding.
Heating system
The heating system consists of a blower fan
and heater matrix located in the heater box,
with hoses connecting the heater matrix to the
engine cooling system, and the heater/air
conditioning control head on the dashboard.
Hot engine coolant is circulated through the
heater matrix passages all the time the engine
is running. Switching the heater on opens a
flap door to direct air through the heater
matrix, and the warmed air enters the
passenger compartment. A fan switch on the
control head activates the blower motor,
which forces more air through the heater
matrix, giving additional heater output for
demisting, etc.
Air conditioning system
The air conditioning system consists of a
condenser mounted in front of the radiator, an
evaporator mounted adjacent to the heater
matrix, a compressor mounted on the engine,
a filter-drier (receiver-drier) which contains a
high-pressure relief valve, and the plumbing
connecting all of the above components.
A blower fan forces the warmer air of the
passenger compartment through the
evaporator matrix (a radiator-in-reverse),
transferring the heat from the air to the
refrigerant. The liquid refrigerant boils off into
low-pressure vapour, taking the heat with it
when it leaves the evaporator.
Note: Refer to the precautions at the start
of Section 12 concerning the potential
dangers associated with the air conditioning
system.
2 Antifreeze-
general information
Warning: Do not allow antifreeze
to come in contact with your skin
or painted surfaces of the
vehicle. Rinse off spills
immediately with plenty of water. If
consumed, antifreeze can be fatal;
children and pets are attracted by its
sweet taste, so wipe up garage floor and
drip pan coolant spills immediately. Keep
antifreeze containers covered, and repair
leaks in your cooling system as soon as
they are noticed.
The cooling system should be filled with a
60/40% water/ethylene-glycol-based anti-
freeze solution, which will prevent freezing
down to approximately -27°C (-17°F). The
antifreeze also raises the boiling point of thecoolant, and (if of good quality) provides
protection against corrosion.
The cooling system should be drained,
flushed and refilled at the specified intervals
(see Chapter 1). Old or contaminated
antifreeze solutions are likely to cause
damage, and encourage the formation of rust
and scale in the system. Use distilled water
with the antifreeze, if available, or clean
rainwater. Tap water will do, but not if the
water in your area is at all “hard”.
Before adding antifreeze, check all hose
connections, because antifreeze tends to
search out and leak through very minute
openings. Engines don’t normally consume
coolant, so if the level goes down, find the
cause and correct it.
The antifreeze mixture should be
maintained at its correct proportions; adding
too much antifreeze reduces the efficiency of
the cooling system. If necessary, consult the
mixture ratio chart on the antifreeze container
before adding coolant. Hydrometers are
available at most car accessory shops to test
the coolant. Use antifreeze which meets the
vehicle manufacturer’s specifications.
3 Thermostat-
check and renewal
1
Warning: Do not remove the
radiator cap, drain the coolant, or
renew the thermostat until the
engine has cooled completely.
Check
1Before assuming the thermostat is to blame
for a cooling system problem, check the
coolant level, drivebelt tension (see Chapter 1)
and temperature gauge (or warning light)
operation.
2If the engine seems to be taking a long time
to warm up (based on heater output or
temperature gauge operation), the thermostat
is probably stuck open. Renew the
thermostat.
3If the engine runs hot, use your hand to
check the temperature of the upper radiator
hose. If the hose isn’t hot, but the engine is,
the thermostat is probably stuck closed,preventing the coolant inside the engine from
circulating to the radiator. Renew the
thermostat.
Caution: Don’t drive the vehicle
without a thermostat. The engine
will be very slow to warm-up in
cold conditions, resulting in poor
fuel economy and driveability. A new
thermostat is normally an inexpensive
component anyway.
4If the upper radiator hose is hot, it means
that the coolant is flowing and the thermostat
is at least partly open. Consult the “Fault
finding” Section at the rear of this manual for
cooling system diagnosis.
Renewal
All models
5Disconnect the negative cable from the
battery.
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you
have the correct activation code
before disconnecting the battery.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
6Drain the cooling system (see Chapter 1). If
the coolant is relatively new or in good
condition, save it and re-use it.
M10 engines
7The thermostat is located in the bottom
hose. First remove the cooling fan.
8Note the fitted position of the thermostat,
then unscrew the hose clamps and withdraw
the thermostat from the hose connections
(see illustration).
9Refit the thermostat-to-hose connections,
and tighten the hose clamps.
10Refit the cooling fan.
M20 and M30 engines
11Loosen the hose clamp (see illustration),
then detach the hose(s) from the thermostat
cover.
3•2 Cooling, heating and air conditioning systems
3.11 On M20 and M30 engine models,
loosen the hose clamp (A) and disconnect
the hose from the thermostat housing
cover - note that the coolant temperature
sender unit (barely visible behind the fuel
pressure regulator) is located at the top of
the thermostat housing (B)
3.8 On the M10 (four-cylinder) engine, the
thermostat (arrowed) is connected in-line
in the radiator hose

12If the outer surface of the fitting that
mates with the hose is deteriorated (corroded,
pitted, etc.), it may be damaged further by
hose removal. If it is, a new thermostat
housing cover will be required.
13Remove the bolts and detach the housing
cover. If the cover is stuck, tap it with a soft-
faced hammer to jar it loose. Be prepared for
some coolant to spill as the gasket seal is
broken.
14Note how it’s fitted, then remove the
thermostat.
15Stuff a rag into the engine opening, then
remove all traces of old gasket material (if the
gasket is paper type). Otherwise, remove the
rubber O-ring (see illustration)and sealant
from the housing and cover with a gasket
scraper. Remove the rag from the opening
and clean the gasket mating surfaces.
16Fit the new thermostat and gasket in the
housing. Make sure the correct end faces out
- the spring end is normally directed towards
the engine.
17Refit the cover and bolts. Tighten the
bolts to the torque listed in this Chapter’s
Specifications.
M40 engines
18Remove the cooling fan and timing belt
upper cover.
19Unscrew the hose clamp and detach thebottom hose from the elbow on the front of
the cylinder head.
20Unbolt the elbow from the cylinder head.
Note the fitted position of the thermostat, then
remove it (see illustrations). Remove the
rubber O-ring; a new one will be needed for
reassembly.
21Locate the thermostat in the cylinder head
in the same position as noted during removal
(arrow pointing upwards).
22Press a new O-ring in the groove, and
locate the elbow on the cylinder head. Tighten
the bolts.
23Connect the bottom hose to the elbow,
and tighten the hose clamp.
24Refit the upper timing belt cover and
cooling fan.
All models
25Refill the cooling system (see Chapter 1).
26Connect the battery negative cable.
27Start the engine and allow it to reach
normal operating temperature, then check for
leaks and proper thermostat operation (as
described earlier in this Section).
4 Radiator-
removal and refitting
1
Warning: Wait until the engine is
completely cool before beginning
this procedure.Note: If the radiator is being removed because
it is leaking, note that minor leaks can often be
repaired without removing the radiator, using
a radiator sealant.
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you
have the correct activation code
before disconnecting the battery.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
Removal
1Disconnect the battery negative cable.
2Drain the cooling system (see Chapter 1). If
the coolant is relatively new, or in good
condition, save it and re-use it.
3Loosen the hose clamps, then detach the
hoses from the radiator (see illustrations). If
they’re stuck, grasp each hose near the end
with a pair of water pump pliers, twist gently
to break the seal, then pull off - be careful not
to distort or break the radiator outlets! If the
hoses are old or deteriorated, cut them off
and refit new ones.
4On M20 and M30 engines, disconnect the
reservoir hose from the radiator filler neck.
5Remove the screws or plastic fasteners that
attach the shroud to the radiator, and slide the
shroud towards the engine (see illustration).
On some engines it is possible to completely
remove the shroud.
6If the vehicle has automatic transmission,
Cooling, heating and air conditioning systems 3•3
3.20b Removing the thermostat
(M40 engine)3.20a Removing the elbow from the
cylinder head (M40 engine)3.15 On M20 and M30 engine models,
after the housing and thermostat have
been removed, take the O-ring out of the
housing and clean the recess in the
housing to be sure of a good seal upon
reassembly
4.5 Plastic fastener retaining the radiator
shroud on some engines4.3b Bottom hose connection to the
radiator4.3a Disconnecting the top hose from the
radiator
3