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View Full Version : 12v Timing belt tensioner failed. Recomendations?



TheBlizz
11-14-2010, 10:37 PM
Here's the skinny. I drive the car to work, then to the Audi stealership, then home and park it. ~75 miles. No odd noises. Go out and get in the car to meet up with a friend. Instantly I hear a loud rapping noise under the hood. I think to my self that it's rod knock. Oh boy. Rev it twice, noise dosen't change. Pop the hood. Take a peak. Nothing out of the ordinary, aside from the noise. Get back in the car to shut it off, and before I could it stalls out. Pulled off a timing cover and the t-belt was loose like a goose.

Pull the lock carrier off and sure enough, the tensioner pully seperated. Belt fell off. Rubbed through a timing cover and is chewed up.

5k miles ago I bought the car with the same problem. Tensioner pulley failed, timing belt fell off and bent all the valves. I rebuilt the heads and bought all new gaskets and timing componants. This is getting rediculous.


So does anyone have any idea why my NEW tensioner pulley failed after 5k miles? Is this common? The bearing was SFK brand, I believe. The timing belt brand was Contitech, and the idler bearing was a *** unit. Don't worry, the ***'s still doing his thing.

Now I'm wondering why would 2 different tensioner pulleys fail on the same motor? Is it possible for the sprockets and pullies to be missaligned? I don't know how many miles were on the previous setup before it failed.

Tomorrow I will be doing a leak down test to see which valves got bent. I'm assuming all. When I put this car back together, I think I will buy an OE tensioner bearing. What is a good cheap OEM place to get parts? Or is there a tensioner bearing you guys prefer?

99blueb5
11-15-2010, 08:45 AM
something on the install was incorrect, it could be the bolt that help down the tensioner was over tightened or not tight enough, the bearing in the pully failed, lots of things can happen, time to look for some new heads

NeedingAnAudi
11-15-2010, 08:48 AM
Buy the 12 valve out of my parts car! Only has 105,000 miles

Euromike
11-15-2010, 09:06 AM
Tough break man, that sucks.

I guess your only option is to do the job again, with a new tentioner and double check that its functioning correctly. And if you ever hear that noise again, shut the car off before your belt slips. Good luck

TheBlizz
11-15-2010, 10:02 AM
http://i33.photobucket.com/albums/d79/theblizz/IMG00058-20101114-1703.jpg

There's an image of the failure. The bearing is a rediculous design. The outter diameter is two peices of sheet metal, folded at a 90*, joining at the middle, wrapped around the bearing. One side failed, got bound up and chewed up the belt before it cause it to slide off what was left of the tensioner.

I will be rebuilding the heads AGAIN. Doesn't bother me. But replacing the head gaskets and head bolts does. So anyone know where I can get an OEM tensioner for a good price?

I did the timing belt install correctly. Even set tension the correct way. I was easily able to turn the belt 90 degrees.

Turbo510
11-15-2010, 01:53 PM
That's got me worried. My '96 has 201K, 75K which I've done, never changed any timing components while I've had it. I had the tensioner off once to to the thermostat, everything seemed OK when given a spin. Maybe the dealer is the safe bet for the rollers, in case there are design upgrades only they might have.

99blueb5
11-15-2010, 03:34 PM
That's got me worried. My '96 has 201K, 75K which I've done, never changed any timing components while I've had it. I had the tensioner off once to to the thermostat, everything seemed OK when given a spin. Maybe the dealer is the safe bet for the rollers, in case there are design upgrades only they might have.

you NEED to change that belt asap, its overdue, interval is every 70k, you dont want to have to go through the bent valve nightmare, its very cheap insurance, if you get cheap and do it your car is running on hopes and dreams and a 300timing belt vs. 1500 if you bend your valves