Good Morning,

I'm still trying to troubleshoot what is causing an annoying sound during acceleration on higher speeds (60mph). It almost sounds as a whistle, and occasionally a clanking sound, I'm worried the valve is hitting the piston (yickes!). I'm assuming they are two different things.

So... I was wondering: I recently changed the belt, if my mechanic did a bad job with the timing, will it make a particular sound? I get an occasional clicking when letting the car warm up about 10-20% of the time. This sound is different from the clanking I get when accelerating at a higher speed.

Or, I have the vacuum servo problem. Does that make a particular sound? I don't think its that because the sounds is heard coming from the engine, and it happens almost instantanously when pushing the pedal.

I've been frustrated with this for over two weeks and still have no clues. Any ideas?

Thanks again in advance,
Al

thanks guys,

i already talked to the mechanic and will go tomorrow.

if ppl are interested i can post back what the conclusion is...

so far, i'm assuming its the belt tensioner. because it'll happen mostly during high rpm. with that said i looked up prices about 100 for the tensioner and ~75 labor... probably ending in the 200range. again, i still see what the mechanic will say.

out of curiosity, can you notice a bad tensioner by looking at it? or is it a precautionary replacement?

Regards,
Al

Dear Al,

Good p.m. and hope this finds you well. If a tensioner fails on a 960 engine, while the engine is running (even just idling) you're looking at a paying for a new head. If the tensioner fails at highway speeds, a new engine may be needed.

When the tensioner fails, the timing belt breaks or goes slack. The valves - no longer being moved by the camshafts - smash into the tops of the pistons. The valves get bent or broken. This means a head refit or replacement.

Sometimes, the pistons may be damaged to the point that the engine is ruined.

In short, the $200 for a new tensioner is chickenfeed, compared with the likely costs of delaying replacment of a suspect or failing tensioner, or a timing belt that has reached its service life limit.

If you think the noise evidences a failing tensioner, you might want to have your car towed to the mechanic, rather than driving it.

I've seen posts here, in which tensioners failed without any warning. In one case, the mileage was not very high at all. The 960 experts on this board - and I'm not one of them - suggest replacing the tensioner, if the car has more than 130K miles, and it is time to replace the timing belt.

Hope some of this helps you.

Yours faithfully,

spook

Dear Spook,

Thanks for your words of advice. I've heard a lot about the problems the timing belt can do. I never thought the tensioner could be a cause of the damage, if i knew i would have replaced it earliar.

I have 116k on the car, but nonetheless I'm not going to 'pushback' the replacement, like you said, its "chickenfeed".

I did take a look at earliar today to see how bad the it might look. However, I notice some debris between the belt and the top of the cover, cleared that off, and also adjusted the cover to a better position than when I took it off.

I'll try to get back to you'll tomorrow, after I've seen the mechanic... either way i'll probably be there to replace it.

Thanks,
Al

Another possibility is an exhaust gasket leak. Ours made similar sounds (especially until was warmed up). The part is cheap but the labor is expensive.

Hi Al,

Make sure it's not your timing belt tensioner getting ready to go! They do fail and should be replaced when the timing belt is. Hopefully it's something relatively simple.
--
Chris. Halifax N.S. '91 745Ti, 290K km and '91 745 NA, 381K km.

If the timing was that far off you would know it because the car would perform like s@#t!

I would look for a misinstalled cover around the belt which could be rubbing.

Why not take it back to the mechanic. If it didn't make the noise before he worked on it and it did right after, I would think he may have made a boo-boo.

--
'96 965 with 16' wheels at 119K. Had '85 745 Turbo Diesel for 200K.

i'll take it to the mechanic this thursday.

usually, should i expect to be charged for an inspection? I've been to this dealer a couple of times, but i've never gone and asked for an inspection of something. Or is this something that varies? I usually figure out certain probs through brickboard (thanks*).

Thanks again,
Al

p.s. the sounds does not appear when I press on the pedal in neutral. mounts look good, and no sign of loose transmission.

i'll take it to the mechanic this thursday.

usually, should i expect to be charged for an inspection. I've been to this dealer a couple of times, but i've never gone and asked for an inspection of something. Or is this something that varies? I usually figure out certain probs through brickboard (thanks*).

Thanks again,
Al

p.s. the sounds does not appear when I press on the pedal in neutral. mounts look good, and no sign of loose transmission.