oil temperature FORD SIERRA 1988 2.G Routine Manintenance And Servicing Workshop Manual

Engine
Oil filter type:
SOHC and DOHC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion C102
CVH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion C104
Valve clearances (cold):
SOHC:
Inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.20 ± 0.03 mm (0.008 ± 0.001 in)
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.25 ± 0.03 mm (0.010 ± 0.001 in)
DOHC and CVH:
Inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Not applicable (hydraulic cam followers)
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Not applicable (hydraulic cam followers)
Chapter 1
Routine maintenance and servicing
Air cleaner filter element renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
Air cleaner inlet air temperature control check . . . . . . . . . . . . . . . . . .36
Air conditioner refrigerant charge check . . . . . . . . . . . . . . . . . . . . . .26
Automatic transmission brake band adjustment . . . . . . . . . . . . . . . .40
Automatic transmission fluid level check . . . . . . . . . . . . . . . . . . . . . .17
Automatic transmission selector lubrication . . . . . . . . . . . . . . . . . . .28
Auxiliary drivebelt check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Battery electrolyte level check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Battery terminal check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Brake fluid renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
Brake system seal and hose renewal . . . . . . . . . . . . . . . . . . . . . . . . .43
Brake pipe and hose check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Camshaft drivebelt renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
Crankcase ventilation system check . . . . . . . . . . . . . . . . . . . . . . . . .35
Crankcase ventilation vent valve renewal . . . . . . . . . . . . . . . . . . . . . .42
Driveshaft check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Electrical system check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Engine coolant renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
Engine idle speed check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Engine oil and filter renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Engine valve clearance check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Exhaust system check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Final drive oil level check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27Fluid leak check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Fluid level checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Ford Sierra maintenance schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Front and rear brake pad/shoe check . . . . . . . . . . . . . . . . . . . . . . . . .9
Fuel filter renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
Handbrake check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Hinge and lock check and lubrication . . . . . . . . . . . . . . . . . . . . . . . .19
Idle speed linkage clean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Ignition system component check . . . . . . . . . . . . . . . . . . . . . . . . . . .39
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Manual gearbox oil level check . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Mixture adjustment check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Oil filler cap check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Pulse air filter element renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
Radiator matrix and air conditioner condenser clean . . . . . . . . . . . . .25
Road test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Roadwheel security check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Seat belt check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Spark plug renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Steering and suspension security check . . . . . . . . . . . . . . . . . . . . . .29
Tyre checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Underbody inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Wiper blade check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
1•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

1•4Maintenance schedule
Every 250 miles (400 km) or weekly
m mCheck the engine oil level (Section 3)
m mCheck the engine coolant level (Section 3)
m mCheck the brake fluid level (Section 3)
m mCheck the power steering fluid level (Section 3)
m mCheck the screen washer fluid level (Section 3)
m mVisually examine the tyres for tread depth, and wear
or damage (Section 4)
m mCheck and if necessary adjust the tyre pressures
(Section 4)
m mCheck and if necessary top-up the battery electrolyte
level - where applicable (Section 6)
m mCheck the operation of the horn, all lights, and the
wipers and washers (Sections 5 and 7)
Every 6000 miles (10 000 km) or
6 months - whichever comes sooner
m mRenew engine oil and filter (Section 8)
m mCheck brake pads or shoes for wear (front and rear)
(Section 9)
m mCheck operation of brake fluid level warning indicator
(Section 9)
m mInspect engine bay and underside of vehicle for fluid
leaks or other signs of damage (Section 10)
m mCheck function and condition of seat belts
(Section 11)
m mCheck condition and security of exhaust system
(Section 12)
m mCheck tightness of wheel nuts (Section 13)
m mClean oil filler cap (Section 14)
m mCheck idle speed (where applicable) (Section 15)
m mCheck mixture adjustment (where applicable)
(Section 16)
Every 12 000 miles (20 000 km) or
12 months - whichever comes sooner
m mCheck automatic transmission fluid level (engine hot)
(Section 17)
m mCheck manual gearbox oil level (Section 18)
m mCheck operation of latches, check straps and locks;
lubricate if necessary (Section 19)
m mRenew spark plugs (Section 20)
m mCheck condition and tension of auxiliary drivebelt(s);
adjust or renew as necessary (Section 21)
m mCheck tightness of battery terminals, clean and
neutralise corrosion if necessary (Section 22)
m mCheck engine valve clearances - SOHC only
(Section 23)
m mCheck handbrake mechanism (Section 24)
Every 24 000 miles (40 000 km) or
2 years - whichever comes sooner
m mCheck air cleaner inlet air temperature control
operation (carburettor models) (Section 36)
m mRenew pulse air filter element (1.6 litre CVH)
(Section 37)
m mRenew air cleaner element (Section 38)
m mClean and inspect distributor cap and HT leads
(Section 39)
m mCheck automatic transmission brake band
adjustment (Section 40)
m mRenew fuel filter (fuel-injection models only)
(Section 41)
m mRenew crankcase ventilation vent valve (SOHC and
DOHC) (Section 42)
m mClean radiator matrix and air conditioning condenser
fins (where applicable) (Section 25)
m mCheck air conditioning refrigerant charge (where
applicable) (Section 26)
m mCheck final drive oil level (Section 27)
m mLubricate automatic transmission selector/kickdown
linkage (Section 28)
m mCheck security and condition of steering and
suspension components, gaiters and boots
(Section 29)
m mCheck condition and security of driveshaft joints and
gaiters (Section 30)
m mInspect underbody and panels for corrosion or other
damage (Section 31)
m mInspect brake pipes and hoses (Section 32)
m mClean idle speed control linkage at throttle (where
applicable) (Section 33)
m mRoad test and check operation of ABS (Section 34)
m mCheck crankcase ventilation system (Section 35)
Every 36 000 miles (60 000 km) or
3 years - whichever comes sooner
m mRenew brake hydraulic system seals and hoses if
necessary (Section 43)
m mRenew brake hydraulic fluid (Section 44)
m mRenew camshaft drivebelt (optional on SOHC
models - compulsory on CVH) (Section 45)
m mRenew coolant (Section 46)
Every 12 000 miles (20 000 km) or
12 months - whichever comes sooner
(continued)

4Carefully check the condition of all coolant,
fuel, power steering and brake hoses. Renew
any hose which is cracked, swollen or
deteriorated. Cracks will show up better if the
hose is squeezed. Pay close attention to the
hose clips that secure the hoses to the system
components. Hose clips can pinch and
puncture hoses, resulting in leaks. If wire type
hose clips are used, it may be a good idea to
replace them with screw-type clips.
5With the vehicle raised, inspect the fuel
tank and filler neck for punctures, cracks and
other damage. The connection between the
filler neck and tank is especially critical.
Sometimes a rubber filler neck or connecting
hose will leak due to loose retaining clamps or
deteriorated rubber.
6Similarly, inspect all brake hoses and metal
pipes. If any damage or deterioration is
discovered, do not drive the vehicle until the
necessary repair work has been carried out.
Renew any damaged sections of hose or pipe.
7Carefully check all rubber hoses and metal
fuel lines leading away from the petrol tank.
Check for loose connections, deteriorated
hoses, crimped lines and other damage. Pay
particular attention to the vent pipes and
hoses which often loop up around the filler
neck and can become blocked or crimped.
Follow the lines to the front of the vehicle
carefully inspecting them all the way. Renew
damaged sections as necessary.
8From within the engine compartment,
check the security of all fuel hose attachments
and pipe unions, and inspect the fuel hoses
and vacuum hoses for kinks, chafing and
deterioration.
9Where applicable, check the condition of
the oil cooler hoses and pipes.
10Check the condition of all exposed wiring
harnesses.
1Periodically check the belts for fraying or
other damage. If evident, renew the belt.
2If the belts become dirty, wipe them with a
damp cloth using a little detergent only.
3Check the tightness of the anchor bolts and
if they are ever disconnected, make quite sure
that the original sequence of fitting of
washers, bushes and anchor plates is
retained.
With the vehicle raised on a hoist or
supported on axle stands, check the exhaust
system for signs of leaks, corrosion or
damage and check the rubber mountings for
condition and security. Where damage or
corrosion are evident, renew the system
complete or in sections, as applicable, using
the information given in Chapter 4.With the wheels on the ground, slacken each
wheel nut by a quarter turn, then retighten it
immediately to the specified torque.
Remove and clean the oil filler cap of any
sludge build-up using paraffin.
Inspect the vent hose for blockage or
damage. A blocked hose can cause a build-
up of crankcase pressure, which in turn can
cause oil leaks.
Ford VV carburettor
1Ensure that the air cleaner is correctly fitted,
and that all vacuum hoses and pipes are
securely connected and free from restrictions,
then run the engine until it is at normal
operating temperature.
2Stop the engine, and connect a tachometer
and an exhaust gas analyser in accordance
with the manufacturer’s instructions.
3Start the engine and run it at 3000 rpm for
30 seconds, ensuring that all electrical loads
are switched off (headlamps, heater blower
etc), then allow the engine to idle and check
the idle speed and CO content. Note that the
CO reading will initially rise, then fall and finally
stabilise after between 5 and 25 seconds.4If necessary, adjust the idle speed screw to
give the specified idle speed (see
illustration).
5Checking and adjustment should be
completed within 30 seconds of the meter
readings stabilising. If this has not been
possible, repeat paragraphs 3 and 4, ignoring
the reference to starting the engine.
Weber 2V carburettor
Models without stepper motor
6Proceed as described for the Ford VV
carburettor but note the following:
7It is permissible to loosen the air cleaner
securing screws to allow easier access to the
carburettor adjustment screws but ensure
that all vacuum hoses and pipes are securely
connected. For adjustment screw location
(see illustrations).
Models with stepper motor (ESC II
system)
8The idle speed is controlled by the ESC II
module via the stepper motor. The only idle
speed adjustment possible is provided by the
“idle speed adjustment” wire, which can be
earthed to raise the idle speed by 75 rpm. No
other method of idle speed adjustment should
be attempted. If the idle speed is incorrect,
the problem should be referred to a Ford
dealer, as the problem probably lies in the
ESC II module for which special diagnostic
equipment is required.
15Engine idle speed check
14Oil filler cap check
13Roadwheel security check
12Exhaust system check
11Seat belt check
Every 6000 miles or 6 months 1•11
1
15.7b Weber 2V carburettor adjustment
screw locations - 1.6 litre models
A Idle mixture screwB Idle speed screw
15.7a Weber 2V carburettor adjustment
screw locations - 2.0 litre models up to 1985
A Idle speed screwB Idle mixture screw
15.4 Ford VV carburettor adjustment screw
locations
A Idle speed screwB Idle mixture screw
Caution: Refer to the
precautions in Section 1,
Chapter 4, Part A or B (as
applicable), before proceeding.
Before carrying out any carburettor
adjustments, ensure that the ignition
timing and spark plug gaps are set as
specified. To carry out the adjustments an
accurate tachometer and an exhaust gas
analyser (CO meter) will be required.

25Start the engine and run it at 3000 rpm for
15 seconds, ensuring that all electrical loads
(headlamps, heater blower etc) are switched
off, then allow the engine to idle and check
the CO content. Note that the CO reading will
initially rise, then fall and finally stabilise.
26If adjustment is necessary, remove the
tamperproof cap from the base of the airflow
meter, and turn the mixture screw using a
suitable Allen key to give the specified CO
content (see illustration).
27Checking and adjustment should be
completed within 30 seconds of the meter
readings stabilising. If this has not been
possible, run the engine at 3000 rpm, for 15
seconds, then allow the engine to idle. Re-
check the CO content and carry out further
adjustment if necessary.
28On completion of adjustment, stop the
engine and disconnect the tachometer and
exhaust gas analyser. Fit a new tamperproof
cap to the mixture screw.2.0 litre DOHC models
29On models with a catalytic converter, the
mixture is controlled by the EEC IV module.
No manual adjustment is possible.
30On models without a catalytic converter,
the idle mixture can be adjusted as follows:
31Run the engine until it is at normal
operating temperature.
32Stop the engine, and connect a
tachometer and an exhaust gas analyser in
accordance with the equipment
manufacturer’s instructions.
33Start the engine and run it at 3000 rpm for
15 seconds, ensuring that all electrical loads
(headlamps, heater blower, etc) are switched
off. Allow the engine to idle, and check the CO
content. Note that the reading will initially rise,
then fall and finally stabilise.
34If adjustment is necessary, remove the
cover from the mixture adjustment
potentiometer (located at the rear right-handside of the engine compartment, behind the
MAP sensor), and turn the screw to give the
specified CO content (see illustrations).
35If adjustment does not produce a change
in reading, the potentiometer may be at the
extreme of its adjustment range. To centralise
the potentiometer, turn the adjustment screw
20 turns clockwise followed by 10 turns anti-
clockwise, then repeat the adjustment proce-
dure.
36Checking and adjustment should be
completed within 30 seconds of the meter
readings stabilising. If this has not been
possible, run the engine at 3000 rpm for 15
seconds, then allow the engine to idle. Re-
check the CO content, and carry out further
adjustments if necessary.
37On completion of adjustment, stop the
engine, and disconnect the tachometer and
the exhaust gas analyser. Refit the cover to
the adjustment screw.
1Fluid level should be checked with the
transmission at operating temperature (after a
run) and with the vehicle parked on level
ground.
2Open and prop the bonnet. With the engine
idling and the handbrake and footbrake applied,
move the gear selector through all positions
three times, finishing up in position “P”,
3Wait one minute. With the engine still idling,
withdraw the transmission dipstick (see
illustration).Wipe the dipstick with a clean
lint-free rag, re-insert it fully and withdraw it
again. Read the fluid level at the end of the
dipstick: it should be between the two
notches.
4If topping-up is necessary, do so via the
dipstick tube, using clean transmission fluid of
the specified type (see illustration).Do not
overfill.
5Stop the engine, refit the dipstick and close
the bonnet.6Note that if the fluid level was below the
minimum mark when checked or is in
constant need of topping-up, check around
the transmission for any signs of excessive
fluid leaks.If present, leaks must be rectified
without delay.
7If the colour of the fluid is dark brown or
black this denotes the sign of a worn brake
band or transmission clutches, in which case
have your Ford dealer check the transmission
at the earliest opportunity.1Place the vehicle over a pit, or raise and
support it at front and rear. The vehicle must
be level for an accurate check.
2If the gearbox is hot after a run, allow it to
cool for a few minutes. This is necessary
because the oil can foam when hot and give a
false level reading.
18Manual gearbox oil level
check17Automatic transmission fluid
level check
Every 12 000 miles or 12 months 1•13
1
16.34b . . . to enable mixture adjustment -
DOHC models
17.4 Topping-up the transmission fluid17.3 Automatic transmission dipstick
location and markings
16.34a Remove the cover from the mixture
adjustment potentiometer . . .16.26 Adjusting the idle mixture -
SOHC models
Every 12 000 miles (20 000 km) or 12 months

5Numbering from the front (camshaft
sprocket) end of the engine, the exhaust
valves are 1, 3, 5 and 7, and the inlet valves
are 2, 4, 6 and 8.
6Turn the engine clockwise using a suitable
socket on the crankshaft pulley bolt, until the
exhaust valve of No 1 cylinder (valve No 1) is
fully closed; ie the cam lobe is pointing
vertically upwards (see illustration).
7Insert a feeler blade of the correct thickness
(see Specifications) between the cam follower
and the heel of the No 1 valve cam lobe. The
feeler blade should be a firm sliding fit. If not,
loosen the locknut and adjust the ball-pin
position accordingly by turning the adjusternut, then tighten the locknut (see
illustrations). Allowance must be made for
tightening the locknut, as this tends to
decrease the valve clearance. Recheck the
adjustment after tightening the locknut.
8Repeat the procedure given in paragraphs
6 and 7 for the remaining valves. With the
carburettor/inlet manifold fitted, some diffi-
culty may be experienced when adjusting the
exhaust valve clearances, and a suitable
open-ended spanner bent to 90º will be found
helpful.
9Check the condition of the camshaft cover
gasket, and renew if necessary. Fit the gasket
to the camshaft cover ensuring that the
locating tabs and dovetails are correctly
located (see illustration), then refit the
camshaft cover and tighten the securing bolts
in the order shown (see illustration), ensuring
that the spacer plates are in position under
the bolt heads, where applicable.
10On fuel injection models, refit the inlet
manifold bracing strut.
11Where applicable refit the spark plugs.
Reconnect the HT leads and locate them in
the clips on the camshaft cover.
12Where applicable, refit any wires and
hoses to the clips on the camshaft cover and
on carburettor models, refit the air cleaner.
DOHCand CVH engines
13These engines are fitted with hydraulic
cam followers therefore no adjustment is
necessary.
Chock the front roadwheels and jack the
rear wheels clear of the ground, supporting
the vehicle with axlestands.
Check that with the handbrake released,
the rear wheels are free to rotate and no brake
“bind” is evident. The handbrake lever travel
should be between two and four clicks of the
ratchet. If brake “bind” or excessive lever
travel is evident, check the handbrake cable
routing and check the self-adjuster
mechanism for wear or damage. Refer to
Chapter 10 for full service information. Gain access to the radiator matrix by
removing the surrounding body panels, fan
shrouds, etc. Clean dirt and debris from the
matrix using an air jet or water and a soft
brush. Be careful not to damage the fins or
cut your fingers.
Remove the protecting grille and clean any
leaves, insects etc. from the air conditioner
condenser coil and fins. Be very careful not to
damage the condenser fins: use a soft brush, or
a compressed air jet, along (not across) the fins.
1If applicable, remove the radiator grille
being careful not to damage the condenser
fins.
2Check the refrigerant charge as follows.
The engine should be cold and the ambient
temperature should be between 64°and 77°F
(18°and 25°C).
3Start the engine and allow it to idle.
Observe the refrigerant sight glass(see
illustration)and have an assistant switch on
the air conditioning to fan speed III. A few
bubbles should be seen in the sight glass as
the system starts up, but all bubbles should
disappear within 10 seconds. Persistent
bubbles, or no bubbles at all, mean that the
refrigerant charge is low. Switch off the
26Air conditioner refridgerant
charge check
25Radiator matrix and air
conditioner condenser clean
24Handbrake check
1•16Every 12 000 miles or 12 months
23.6 Cam lobe correctly positioned for
checking valve clearance. Insert feeler
gauge as shown by arrow23.7b Adjusting a valve clearance
26.3 Air conditioning system refrigerant
sight glass (arrowed)
23.9b Camshaft cover bolts (A) and spacer
plates (B)
Tighten bolts in following stages:
Stage 1 Bolts 1 to 6
Stage 2 Bolts 7 and 8
Stage 3 Bolts 9 and 10
Stage 4 Bolts 7 and 8 (again)
23.9a Camshaft cover gasket dovetails
23.7a Using a feeler gauge to check a
valve clearance

Steering and suspension
3Check for any abnormalities in the steering,
suspension, handling or road “feel”.
4Drive the vehicle, and check that there are
no unusual vibrations or noises.
5Check that the steering feels positive, with
no excessive “sloppiness”, or roughness, and
check for any suspension noises when
cornering, or when driving over bumps.
Drivetrain
6Check the performance of the engine,
clutch, transmission and driveshafts.
7Listen for any unusual noises from the
engine, clutch and transmission.
8Make sure that the engine runs smoothly
when idling, and that there is no hesitation
when accelerating.9Where applicable, check that the clutch
action is smooth and progressive, that the
drive is taken up smoothly, and that the pedal
travel is not excessive. Also listen for any
noises when the clutch pedal is depressed.
10Check that all gears can be engaged
smoothly, without noise, and that the gear lever
action is not abnormally vague or “notchy”.
Check the operation and
performance of the braking
system
11Make sure that the vehicle does not pull to
one side when braking, and that the wheels
do not lock prematurely when braking hard.
12Check that there is no vibration through
the steering when braking.
13Check that the handbrake operates
correctly, without excessive movement of thelever, and that it holds the vehicle stationary
on a slope.
14Test the operation of the brake servo unit
as follows. With the engine off, depress the
footbrake four or five times to exhaust the
vacuum. Start the engine, holding the brake
pedal depressed. As the engine starts, there
should be a noticeable “give” in the brake
pedal as vacuum builds up. Allow the engine
to run for at least two minutes, and then
switch it off. If the brake pedal is depressed
now, it should be possible to detect a hiss
from the servo as the pedal is depressed.
After about four or five applications, no further
hissing should be heard, and the pedal should
feel considerably firmer.
1Inspect the crankcase ventilation system
for blockage or damage. A blocked hose can
cause a build-up of crankcase pressure,
which in turn can cause oil leaks (see
illustration).
2On carburettor model SOHC engines, clean
the oil filler cap with paraffin and check that
the vent valve is not blocked by pulling it from
the oil separator and loosening the hose clip
(Section 42).
3On CVH engines, check that the oil
separator and mushroom valve are not
blocked, and clean if necessary (see
illustration).
35Crankcase ventilation system
check
SOHC and DOHC carburettor
models
1A vacuum pump will be required to test the
control components.2To check the operation of the air
temperature control, the engine must be cold.
First observe the position of the flap valve
which should be fully closed prior to starting
the engine(see illustration).The position of
the flap can be observed by disconnecting the
cold air inlet hose from the air cleaner spout
and looking into the spout.
3Start the engine and allow it to idle. Check
that the flap is now fully open to admit hot air
from the exhaust manifold shroud. If the flap
does not fully open, stop the engine and
check the vacuum diaphragm unit and heat
sensor as follows (see illustrations).4Working under the base of the air cleaner
body, disconnect the diaphragm unit-to-heat
sensor vacuum pipe at the sensor end, and
connect a vacuum pump to the diaphragm unit.
Apply a vacuum of 100.0 mm (4.0 in) of mercury.
5If the flap opens, then the heat sensor is
faulty and should be renewed. If the flap
remains closed, then the diaphragm unit is
faulty, and a new air cleaner body will have to
be obtained, as the diaphragm unit is not
available separately.
6On completion of the checks, disconnect
the vacuum pump, and reconnect the vacuum
pipe and cold air inlet hose.
36Air cleaner inlet air
temperature control check
1•18Every 24 000 miles or 2 years
35.1 Loosening the crankcase ventilation
hose clip - CVH models
36.3b Air cleaner heat sensor viewed from
inside air cleaner - OHC models36.3a Air cleaner vacuum diaphragm unit -
OHC models
36.2 Air cleaner flap valve operation -
OHC models
A Flap fully open to admit hot air
B Flap fully closed to admit cold air
35.3 Oil separator (1) and mushroom valve
(2) locations in air cleaner - CVH models
Every 24 000 miles (40 000 km) or 2 years