pntbllfun

i had a timing belt job done about 10K miles ago. a strange rattle started to happen a couple months ago. when i brought it to a mechanic they instantly said water pump was going. but i know that was just recently replaced and i assume they just wanted my money to do an expensive job that was unnecessary.

from doing some research and troubleshooting i have figured out there is something wrong with the whatever is keeping my timing belt under tension. when the engine makes this wierd rattling noise (i think it is the cams are very slightly out of time) the timing belt has no tension on it. i took off the TB covers and felt the belt. you could move it up and down at least an inch, no tension on it.

the rattling noise will go away almost instantly and the TB will be under tension again. what do you think is causing the belt to lose tension then regain it again?

4Driver4

Stop driving the car. Do not even start the engine.

Take a look at the timing belt tensioner. Sounds like it is failing.

pntbllfun

i mean it has ebough tension to holt the belt to the cam sprockets, so i dont think the belt is going to like fall of or anything and damage the engine.

how long do you think it will take to put in service position and remove everything to get at the tensioner and replace it? and is that the only thing that could be causing the problem

4Driver4

If the belt has that much slop, it could very easily jump several teeth.

You'll need about 4 hours and the locking pin and bar.

pntbllfun

i am wondering how the tensioner stops putting tension on the belt then regains tension again.

i would think that it just would lose tension and that would be it, i dont see how it goes in between the two

Peter Badore

You are asking an interesting question but the issue is how much longer before the timing belt skips several teeth and bents some valves or worse. Last month I took apart an AHA V6 that broke six exhaust valves and completely destroyed an engine on a 99 A6 Avant.

4Driver4

It doesn't. The slop in the belt just moves to a different area. Don't forget that the cams have all kinds of spring forces acting on them from the valve springs. When you get all the timing belt covers of and turn the engine over by hand you will see what I mean.