2001 A6 4.2 with 75k mis. Several folks say to change it now due to age, even though it looks to be in great shape and the Audi suggested interval is 105k. The job is very expensive at the dealer and even at indy's. Bentley doesn't make it look that bad, given the proper tools (cam bar, crank pin).

Has anyone done the 4.2? Wondering if it's doable over a weekend, or even one day. I've done fairly serious mechanical work on American cars/trucks, but am new to the Audi game.

Thanks for your replies.

 

Yes you should definatley change the belt simply due to the age. If it breaks or strips some teeth, it is VERY expensive when the valves and pistons try to occupy the same space at the same time! Not a pretty site, and I've seen it first hand..........It's fairly straight forward, provided as you mentioned, you have the correct tools. The most important one is the cam "bar". You can't do the job without it. Another thing is the special puller to "pop" the sprockets loose off the tapered cam noses so they freewheel. The crank pin isn't as critical, there is a timing mark on the crank pulley and lower belt cover. You will have to put the lock carrier into "service position", again not that big of a deal (pull the bumper cover, and a few fasteners and slide it forward a couple inches on some guide pins placed one on each side where the bumper shock bolts were. Then it just a matter of pulling the ribbed belt, tensioner, crank pulley, etc and the plastic belt covers. It's probably doable in a day at home without a hoist. At work, it's about a 4 hour job (give or take). Main thing is to follow the manual TO THE LETTER as to torques, tensioning procedure etc. Triple check the timing before reassembly by turning the crank two revs and making sure the cam bar will slip into the holes easily. If not, loosen and pop the sprockets loose again and redo it. Can't remember for sure on the '01 4.2 but, if the water pump is driven by the toothed belt, change it while your in there and save some grief later on! Also should replace at least the tensioner pulley too, cheap insurance. If you've done serious work on American cars, you shouldn't have too much trouble. I worked on Fords for 22 years ('85-'07) starting with Audi the fall of '07 and picked up the 2.7L, 2.8L, 4.2L timing belt service pretty quick. As for those darn 3.0L's.....................................whole different animal! Good luck!

 

Thanks very much for your reply!

There are a couple of items in the procedure that confuse me. It looks in the book like the cam locking bar is held on by the cam sprocket bolts, but then it says to loosen the cam sprocket bolts 5 turns, then remove the bar. Do the sprocket bolts not have to be removed to put the locking bar on to begin with?

Then it says to pop the sprockets off the cams so they spin on the cams. What then keeps the cams from rotating? I thought the cam locking bar was to keep the cams from rotating, but we're putting it on and taking it off.

Also, when tightening cam sprocket bolts, wouldn't the cam want to turn? Maybe there is something keyed to the cams to prevent that?

Do both cam sprockets need to be loosened? Bentley says yes, while the other OEM software manual says just the sprocket for cyls. 1-4.

One final question: if the tension is released from the belt, as the manual says, what is the point of taking the cam sprockets loose? Can't the belt be removed and replaced without doing that?

Thanks again for any replies! I'm not intimidated by the procedure, but I do want to make sure I fully understand it.

 

The cam locking bar actually has 2 dowels on each end and a hole over the cam bolts so you can access them with the socket. On the end of each cam is a diamond shaped (sort of) plate that goes over flats on the cam nose. The sprockets themselves are seperate pieces that go onto a taper (similar to a flywheel on a lawnmower engine). The bar locks into the plates which are on the flats and holds the cams in position even if the sprockets are freewheeling. You do have to remove the bar to pop the sprockets loose with the puller. Be carefull you don't accidentally turn the cam. Hold the puller with one hand while tightening the forcing screw and you should be OK. If it does spin, (it does happen sometimes)it's not enough force to damage any valves.. Once the sprockets are loose, the trick is to screw the bolts in far enough so the plates are snug on the cams and the sprockets can still turn. You don't want any slop in the pieces at this point or the timing will be off. When torquing the bolts afterwards, the bar holds everything in place.

The reason for having both sprockets loose is to be sure the cams are in exact time and also for proper tensioning of the belt. You have to follow the tensioning procedure exactly. Don't try to do it with only one of them loose. It only takes having one cam a couple degrees off to turn on the check engine lamp because the crank sensor signal and cam sensor signals will be out of "sync". Can't recall off hand the exact terminology.

If you follow the Bentley manual step by step and to the letter, it'll come out good. Hope I've helped more than confused! Sometimes it's hard to explain things in text only.

 

You've helped a lot. Thank you.

 

Update, if you're interested:

Started and finished the job a couple of days ago. Replaced the usual stuff - timing belt, tensioner, roller, eccentric pulley, hydraulic damper, water pump, thermostat, accessory belt and tensioner, as well as the coolant pressure tank.

I didn't touch the cam or crank seals. There really isn't a DIY on the tube for the A6 4.2 timing job, so I used a combination of ElsaWin directions, a little bit of Bentley (book, not software, which was of marginal use), and the very good instructions that came with the Conti timing kit (from Partsgeek.com).

I do have to wonder, why didn't Audi make the car 3" longer so we could skip all that bumper removal and lock carrier business, which I found to be a royal PIA. I won't be in a hurry to remove and replace the bumper again.

Special tools purchased and used were the 40V cam lock bar T40005, 3242 crank pin (easy to get in but hard to get the little plug back in the block since my hand doesn't fit up there), and the odd little tool for tensioning the belt on the eccentric pulley. I made a fan holding tool from a pair of 90 deg. longnose pliers with the ends cut off, and also had to cut down an 8mm L Allen to tighten that eccentric pulley while using the funny little tool.

The job took ALL day, reading and re-reading the directions, checking the cam alignment 10+ times, putting that damn bumper back on, which came off fine but didn't go on fine.

Anyway, timing is perfect, no leaks, everything sounds good. Drove about 200 miles so far with no apparent ill effects. Should be good for another 80-90k.

 

Actually give it some more time you'll be able to take that bumper and lock carrier out in 10 minutes.

Sorry to say.

 

2nd. Its amazing how quick you get after a while.

 

By any chance do you still have those instructions from parts geek i have the 2001 audi a6 4.2l v8 awd. I bought the same kit from parts geek and lost those instructions. Would you mind sending me a picture of them id really appreciate it. Ive been going crazy looking for them al day.