i am about to replace cam tensioner seals and i read somewhere that before i loosen the tensioners i need to make sure that i am at TDC. is this right? if so how is it done?

 

At TDC you'll notice that the oblong plates at the ends of the camshafts are pointing towards each other, with the big hole on each closer to the center of the engine. Also there's a little notch scratched in the accessory belt's main pulley that correponds to a little arrow in the plastic cover that's mounted directly behind it. this is only true for the 12v V6s.

 

is this possible to see without putiing front emd in service position? i'm just doing cam tensioner seals and valve cover gaskets.

 

it should be although you do have to pull off the t-belt covers. anythings possible with little hands, i changed my thermostat on my a4 without putting it in service position.

 

You can change the valve cover gaskets and tensioners without putting it into the service position, but you do need the correct special tool to remove tension from the cam chain tensioners

 

Belt drive assembly[/align]Removing and installing toothed belts[/align]
Removing:










β€’Remove ribbed belts β€’β†’ Remove engine cover -C- Remove bolts to do so -arrows-. [/ul]











β€’β†’ Remove pressure hoses -arrows- from intercoolers to left and right-hand pressure piping. [/ul]










β€’β†’ Remove pressure piping -1-. [/ul]
Note:
Be careful of retainer strips -2-.











β€’β†’ Remove ribbed belt tensioner -1-.
β€’Remove left and right toothed belt protector -2-.
β€’Remove central toothed belt protector -3-. [/ul]










β€’β†’ Turn over engine manually to TDC position. Markings -A- and -B- must be opposite each other. [/ul]
Note:
To turn over engine, use central crankshaft bolt.

β€’Checking camshaft positioning: The large drill holes on the camshaft sprocket fixing plates must face inwards and be directly in line with each other, otherwise rotate the crankshaft one more turn. [/ul]


β€’Unscrew sealing plugs from left-hand cylinder block. [/ul]










β€’The TDC drilling in the crankshaft must be located directly behind the sealing plug hole (visually or by touch).[/ul]
Important:
[/align]
β€’β†’ Screw in 3242 crankshaft retainer into sealing plug hole and tighten.[/ul]










β€’β†’ Remove crankshaft vibration damper. [/ul]
Note:
It is not necessary to loosen the central bolt to remove the vibration damper.











β€’β†’ Remove ribbed belt idler wheel -arrows-.
β€’Remove toothed belt protector underneath vibration damper
-arrows-. [/ul]
Notes:

β—†Before removing belt, mark direction of rotation with chalk or felt-tipped pen. Running a used belt in the opposite direction could destroy it. [/ul]










β—†Toothed belt tensioner is oil damped and can only be compressed by applying an even pressure slowly. [/ul]

β€’β†’ Turn toothed belt tensioner -1- in direction of arrows with 8 mm Allen key until tensioning arm -2- has compressed tensioner -3- far enough that special tool T 400 11 fits into drill hole and plunger.
β€’Insert special tool T 400 11, release toothed belt tensioner.
β€’Remove toothed belts. [/ul]
Installing










β€’Insert camshaft retainer 3391 into fixing plates of both camshafts.
β€’Release both camshaft bolts and unscrew approx. 5 turns.
β€’Take out camshaft retainer 3391.
β€’β†’ Pull off both camshaft sprockets using special tool T40001.
β€’Refit both camshaft sprockets with fitting plates and hand-tighten. [/ul]










Note:
The camshaft sprockets should be loose enough on the cones that they can be moved on the camshafts but not tilted.

β€’β†’ position belts on all sprockets as shown in the diagram.
β€’Insert camshaft retainer 3391. [/ul]










β€’β†’ Rotate belt tensioner -1- to the right in arrow direction with 8 mm Allen key until special tool T 400 11 can be removed. [/ul]











β€’β†’ Tension belts by turning with a torque wrench in direction of arrow and torqueing to 15 Nm.
β€’Tighten camshaft sprockets. [/ul]










β€’β†’ Refit ribbed belt idler wheel -arrows-.
β€’Refit toothed belt protector underneath vibration damper -arrows-. [/ul]











β€’β†’ Install vibration damper. Watch for seating noses -arrows- on toothed belt sprocket. [/ul]

β€’Fit toothed belt protector.
β€’Refit ribbed belts [/ul]










Tightening torque




Toothed belt sprocket on camshaft


55 Nm


Idler wheel

45 Nm


Toothed belt tensioner

20 Nm


Pulley on crankshaft

20 Nm


Toothed belt tensioner

10 Nm


Central crankshaft bolt 1)

200 Nm + 180Β°2)
1)The central bolt should be replaced.
2)2 times 90Β°further turning is permitted.



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Servicing valve assembly[/align]Removing and refitting camshafts and camshaft adjusters[/align]
Removing

●Cylinder head fitted [/ul]










β€’β†’ Remove noise insulation -arrows-.
β€’Remove front bumper: [/ul]
=> Body fitting work; Repair group 63; front bumpers; front bumper removal and refitting

β€’Place lock carrier in service position [/ul]
=> Body exterior fitting work; Repair group 50; removal and refitting of lock carrier; lock carrier service position

β€’Remove ribbed belts
β€’Remove toothed belts Left-hand cylinder head:
β€’Remove left-hand cylinder head coverRight-hand cylinder head:
β€’Remove right-hand cylinder head cover All:
β€’Unscrew Hall effect sensor housing (10 Nm)
β€’Unscrew Hall effect sensor cover (20 Nm) and prise out carefully with screwdriver.
β€’Insert camshaft retainer 3391 into fixing plates of both camshafts.
β€’Release both camshaft bolts and unscrew approx. 5 turns.
β€’Take out camshaft retainer 3391. [/ul]










β€’β†’ Pull off both camshaft sprockets using special tool T40001.
β€’Carefully prise out oil pipes for camshaft bearing lubrication from camshaft bearings using a screwdriver. [/ul]
Be careful that retainers do not break off when prising out.











β€’β†’ Secure camshaft adjuster with chain tensioner holder 3366. [/ul]
Note:
Camshaft adjuster can be damaged by over-tightening chain tensioner holder.










β€’β†’ Recheck TDC position of camshafts. [/ul]
Note:
Both markings on camshafts must be directly in line with both arrows on bearing caps.


β€’Clean drive chain and sprockets opposite both arrows on bearing caps and mark fitting position in colour.[/ul]










Notes:

β—†β†’ Distance between both arrows or coloured marks is 16 links of the drive chain.
β—†The groove on the exhaust camshaft is offset a little to the inside of the chain guide -1-.
β—†Do not mark chain by centre punching, grooving, etc.! [/ul]










β€’β†’ Unscrew camshaft adjuster retaining bolt -6-.
β€’Unbolt bearing caps 1, 3, 5 and 7 of the inlet and exhaust camshafts and lay them in sequence on a clean surface.
β€’Loosen bearing caps 2 and 4 of the inlet and exhaust camshafts cross-wise and remove.
β€’Remove inlet and exhaust camshafts complete with camshaft adjuster. [/ul]

Installing










β€’β†’ Replace the bonded rubber bush of camshaft adjuster and apply sealant lightly to hatched surface. [/ul]

β—†Sealant [/ul]
=> Parts List










β€’Lay drive chain on camshaft sprockets as follows:

β€’β†’ If old drive chain is reused, offer up coloured marks -arrows- to grooves. [/ul][/ul]












β€’β†’ If a new drive chain is used, the distance between grooves -A- and -B- on the camshafts must correspond to 16 links of the drive chain. The illustration shows where the 1st and 16th link must be placed on the sprockets.
β€’The groove-A- is offset a little to the inside of the chain guide -1-. [/ul]
Push in camshaft adjuster under chain (2nd mechanic needed).
Lay camshafts with drive chain and camshaft adjuster in cylinder head.
Oil camshaft contact surfaces. [/ul]
Notes:

β—†Fitting sleeves for bearing cap and camshaft adjuster must be in position in cylinder head.
β—†When refitting bearing cap, ensure that cap ID is readable from inlet side of cylinder head. [/ul]










β€’Tighten camshaft adjuster (taking care of fitting sleeves).
β€’β†’ Tighten bearing caps 2 and 4 of the inlet and exhaust camshaft cross-wise (taking care of fitting sleeves).
β€’Refit both bearing caps to inlet and exhaust camshaft sprockets. [/ul]










β€’Recheck setting of camshafts.

β€’β†’ Both markings on camshafts must be directly in line with both arrows on bearing caps -arrows-. [/ul][/ul]












β€’β†’ Distance between both arrows on bearing caps or coloured marks is 16 links of the drive chain.
β€’The groove on the exhaust camshaft is offset a little to the inside of the chain guide -1-. [/ul][/ul]










β€’β†’ Apply sealant lightly to hatched surface of double bearing cap -1- and bearing cap -7- [/ul]











β€’β†’ ...and replace bearing cap (taking care of fitting sleeves). [/ul]

β—†Sealant [/ul]
=> Parts List

β€’Replace remaining bearing caps (taking care of fitting sleeves).
β€’Replace oil pipes for camshaft bearing lubrication and install.
β€’Replace inlet and exhaust camshaft seals, fit β€’Removing chain tensioner holder 3366. [/ul]
Notes:

β—†Engine must not be started for approx. 30 minutes after fitting new tappets. Hydraulic compensating units must seat themselves (otherwise valves impact pistons). Then turn crankcase over twice.
β—†Turn over engine carefully at least twice after working on valve gear to endure that valves do not impact when starting. [/ul]










β€’β†’ Seal bearing cover/cylinder head joints
β€’Apply a small quantity of sealant to the 4 edges on the cylinder head mating surfaces or the seal-arrows- using a small screwdriver before replacing the cylinder head cover. [/ul]

β—†Sealant [/ul]
=> Parts List

β€’Refit cylinder head cover β€’Refit toothed belts
β€’Refit ribbed belts Tightening torques[/ul]








Part



Nm


Bolts

M6

10




M8

20


Deviation of:






Bearing cap on cylinder head



10


Camshaft adjuster on cylinder head

10


Cover for Hall effect sensor on camshaft

25


Housing for Hall effect sensor on cylinder head


10


Camshaft sprocket on camshaft



55 Nm


Cylinder head cover



10

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Like I said before, it is unneeded to place the car in the service position or pull nearly anything that is outlined in the book proceedure that avant 80 have posted. Heres the writeup, http://forums.audiworld.com/a6/msgs/616641.phtml