[s-cars] 94 UrS4 Timing belt

[Paul Heneghan]

> Water pump seal has given up the ghost, so call coolant dumped.
>
> Due to do the timing belt in any case.
> Anyone have a nice writeup for this?
> Particularly timing marks as I can probably muddle my way through the rest
> of it.

Just did this a couple of weeks ago for the same reason.

Obviously did the timing belt while I was in there (even though it was only
a couple of years old). You have to remove the bumper, cross member, and
move the radiator as far forward as possible to get decent access.

Essential reading:
http://www.sjmautotechnik.com/trouble_shooting/S4timing.htm

There are a couple of other pdfs on the web that may be useful. Google ...

Only tips I can think of are what tools are required:
1. Audi crank-locking tool 3256. No idea whether it's still readily
available. I got mine about 10 years ago for about GBP40. I once did an
Audi 5-cylinder without the crank locking tool - not enjoyable at all!

2. Don't bother with the torque-wrench extender 2079. Just buy a
second-hand BIG torque wrench - I got a big Norbar 1000 Nm one off ebay a
few years ago for well under GBP100. Out of interest, I measured the torque
required to loosen the crank bolt on mine (that had been done a couple of
years ago, and a small band of loctite used on reassembly). It took over
700 Nm to loosen. The correct torque for tightening the crank bolt is 450
Nm (if you don't use the 2079 extender). If you use the 2079 extender tool,
then you have to use a torque wrench about 1 m long and a torque of 350 Nm.
Apparently, a later spec from Audi said that the crank bolt should be
torqued to 200 Nm and then tightened a further 180 degrees.

Check the locating key on your crank gear - replace if suspect.



My Bentley manual gives a torque of 20 Nm for the timing belt tensioner
bolts - as do 50% of the guides on the web. That's rubbish - they're only
M6 bolts (10 mm heads) - you'll get to about 15 Nm and then you'll feel the
bolt stretch/strip threads. Eventually I found on Scott Mockry's page a
suggestion that 7 ft lb (10 Nm) was the right torque for those. I added
loctite just to be sure.

Clean up the block properly (400 W&D) before trying to seat your new pump.
a dab of rubber-friendly grease is supposed to be useful to ensure that the
o-ring stays in the groove during assembly.

Replace your turbo coolant return line while you've got everything apart.
It's really difficult to do otherwise. Item #4
http://forums.audiworld.com/showthread.php?t=2832818

Work through the others on the list if you haven't done them already. In
nearly 300k miles of S6 ownerships, I've done most of them at least once.
As well as the obvious POSs and occasional coil packs.

Have fun!

Paul