This is a little upsetting for me. It appears the aluminum alloys Audi used in the A8's is sub-par. I mean this metal is crap.

You see I performed my 90K timing belt service about 2 months ago. Ever since then the driver's rear cam seal and cam seal cover is leaking engine oil. No problem I thought... just remove it and replace the seal again. Mind you I used an air ratchet (during the timing belt service) to put the cam seal cover back on (mind you with a weak air rachet too). Then I torqued it with a quality torque wrench. So about 2 weeks ago I finally decide to fix this leak and this time only used a regular ratchet. I took the cover off, replaced both seals and threaded the bolts back in. I noticed they didn't tighten that well (yes, they were properly threaded) and I took the bolts back out only to find the bolts were fine but the aluminum threads came out and were on the bolts. So I had to go to a lot of trouble and tap new threads -- which I was only able to do with one bolt. It still leaks to this day now... but I chalked this whole event as being my fault because I used an air ratchet and perhaps it stressed the metals.

Well, I was doing an oil change over the weekend and I noticed the front of the engine was noisy. I ruled out the serpertine belt and related devices and realized it was coming from the driver's cam sprocket. I removed the driver's side timing cover and eventually realized the timing belt was a little too loose. Hmm. Okay, so I drained the coolant and removed various devices (like fans, etc) to remove the passenger's side timing cover. Now I started working on the timing eccentric roller and loosened the bolt (with a standard ratchet) tightened the timing belt and then re-tighened the eccentric roller's bolt snug, then got the torque wrench and proceeded to tighten it to the factory spec of 41 ft-lbs. Well, I tightened and then it started turning easy again -- because the damn threads ripped off. Now I've have had several Mercedes and even a 750iL BMW which all had aluminum blocks and heads, and I have never experienced such garbage such as this. The crap metal that Audi uses where bolts consistenly rip their own threads out is maddening and never, ever had this happen with the other cars. The timing roller was done VERY carefully by absolute factory specs and now it's screwed too. I'm sorry for the rant but this is very frustrating and disappointing to experience this from a car of this caliber. (

Any suggestions? Is this a common problem? Is there some sort of trick I don't know about?? What's going on?

Mike M.
1997 A8 4.2

 

I stripped the threads on a 2001 Honda Prelude block before because it was aluminum and I used a light pressure impact wrench. I felt rather stupid afterwards. I took it to a engine shop and they used a helicoil (spelling?) to repair it and I've heard this makes it stronger than the original block anyway. So far no problems with it and it was an easy cheap fix. I never use an impact (even light pressure) on blocks anymore. Just not worth the trouble.

I'm not so sure the Audi block is cheap aluminum, I think you just have to be more careful with any aluminum block.

 

The two M12 socket head cap screws for each of my Alcon calipers bolt into an aluminum adapter that contains Heli-Coil inserts. Also many aluminum block race motors use Heli-Coil inserts for the cylinder head studs.<ul><li><a href="http://www.helicoils.com/">Heli-Coil</a></li></ul>

 

Wow. I never knew about these. I went to the website and I think I found my answer. Thank you very much.

Where can one easily order these? The website just redirects somewhere else. Where do you order them?

Mike M.
1997 A8 4.2Q

 

search for thread insert. There is an insertion tool, and the hole needs to be drilled and tapped ahead of the insert. These things kick ***. Some engine builders use Helicoil inserts on brand new engines to eliminate stripping in aluminum blocks.

 

I work in Aerospace (EVERYTHING is Aluminum) and helicoils are everywhere!!

 

I have a walk-in store near me, but they also have a web site.<ul><li><a href="http://www.fastenal.com/web/home.ex">Fastenal</a></li></ul>