AUDI A6 1995 C5 / 2.G AHA ATQ Engines Valve Gear Service Manual

15-1


Valve gear, servicing

WARNING!

Do not re-use any fasteners that are worn or
deformed in normal use.
Some fasteners are designed to be used only
once, and are unreliable and may fail if used
a second time. This includes, but is not
limited to, nuts, bolts, washers, circlips and
cotter pins. Always follow the
recommendations in this manual-replace
these fasteners with new parts where
indicated, and any other time it is deemed
necessary by inspection.

CAUTION!

After installing new hydraulic valve lifters the
engine must not be started for about 30
minutes (otherwise the valves will strike the
pistons). Turn the crankshaft two complete
revolutions by hand before starting.
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15-2

Notes:

Cylinder heads with small cracks between the
valve seats that are less than 0.3 mm (0.012
in.) wide and/or between one valve seat and
only the first four threads of the spark plug
thread, can continue to be used without
reduced service life.
Carefully apply a small amount of sealant D 454
300 A2 at the four end points of the sealing
surfaces on the cylinder head using a small
screwdriver page 15
-13
.

CAUTION!

Part numbers are listed here for reference
only. Always check with your Parts
department for the latest information.
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15-3


Cylinder head without oil lines to camshaft
bearings

1 -
Double bearing cap
Lightly coat with sealant 454 300 02 A2
before installing page 15
-36

2 -
Bolt
10 Nm (7ft lb)
3 -
Exhaust camshaft bearing cap Watch guide sleeveNote installation position and numbering
page 15
-36

Lightly coat last bearing cap (after chain)
with D454 300 A2 sealant before installing
4 -
Exhaust camshaft Checking axial clearance page 15
-42
Removing and installing page 15
-31

Check radial clearance using Plastigage
(hydraulic valve lifters removed):
Wear limit: 0.1 mm (0.004 in.)Max. run-out: 0.01 mm (0.0004 in.)
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15-4


5 -
Cap
Always replace
6 -
Intake camshaft bearing cap Note installation position and numbering
page 15
-36

7 -
Intake camshaft
Checking axial clearance page 15
-42
Removing and installing page 15
-31

Check radial clearance using Plastigage
(hydraulic valve lifters removed):
Wear limit: 0.1 mm (0.004 in.)Max. run-out: 0.01 mm (0.0004 in.)
8 -
Drive chain Installing page 15
-36
9 -
Bolt
10 Nm (7ft lb)
10 -
Mechanical camshaft adjuster With valve -1- for camshaft adjustment -
N205- Secure using 3366 bracket tensioner
before removing page 15
-31

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15-5


11 -
Hydraulic valve lifter (intake)
Notes page 15
-45
12 -
Valve keepers
13 -
Valve spring retainer
14 -
Valve spring
15 -
Valve stem oil seal
Replacing with cylinder head installed
page 15
-47

16 -
Rubber/metal seal
Always replace
17 -
Seal Always replace
18 -
Cylinder head Removing and installing page 15
-18
Checking for distortion page 15
-27
Resurfacing page 15
-28
19 -
Exhaust valve
20 -
Intake valve
21 -
Oil seal
Camshaft Position (CMP) sensor side
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Replacing page 15
-14
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15-6


22 -
Shutter wheel for Camshaft Position
(CMP) sensor -G40-
Note position (notch on camshaft)
23 -
Washer Conical
24 -
Bolt 25 Nm (18 ft lb)
25 -
Camshaft Position (CMP) sensor -G40-
26 -
Bolt 10 Nm (7 ft lb)
27 -
Bolt 55 Nm (41 ft lb)
28 -
Camshaft sprocket
29 -
Oil seal Toothed belt sideReplacing page 15
-14
30 -
Hydraulic valve lifter
Notes page 15
-45
Removing and installing with cylinder head
installed page 15
-31

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15-7


Cylinder head with oil lines to camshaft
bearings

1 -
Double bearing cap
Lightly coat with 454 300 02 A2 sealant
before installing page 15
-17

2 -
Exhaust camshaft bearing cap
With oil line connectorWatch guide sleeveNote installation position and numbering
page15
-31

Lightly coat last bearing cap (after chain)
with D454 300 A2 sealant before installing
3 -
Bolt 10 Nm (7 ft lb)
4 -
Oil line Exhaust sideFrom VIN 8D-W-005 001For bearing cap lubricationNote installed position Fig. 4
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15-8


5 -
Exhaust camshaft
Checking axial clearance page 15
-42
Removing and installing page 15
-31

Check radial clearance using Plastigage
(hydraulic valve lifters removed):
Wear limit: 0.1 mm (0.004 in.)Max. run-out: 0.01 mm (0.0004 in.)
6 -
Cap Always replace
7 -
Oil line Intake sideFrom VIN 8D-W-005 001Note installed position Fig. 3For bearing cap lubrication
8 -
Intake camshaft bearing cap With oil line connectorNote installation position and numbering
page 15
-36

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15-9


9 -
Intake camshaft
Checking axial clearance page 15
-42
Removing and installing page 15
-31

Check radial clearance using Plastigage
(hydraulic valve lifters removed):
Wear limit: 0.1 mm (0.004 in.)Max. run-out: 0.01 mm (0.0004 in.)
10 -
Drive chain Installing page 15
-36
11 -
Bolt
10 Nm (7ft lb)
12 -
Mechanical camshaft adjuster With valve -1- for camshaft adjustment -
N205- Secure using 3366 bracket tensioner
before removing page 15
-31

13 -
Hydraulic valve lifter (intake)
Refer to notes page 15
-45
Removing and installing with cylinder head
installed page15
-31

14 -
Valve keepers
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