noises from a fan & beltless M20. Engine toast?

[Earendil]

Please help me identify this noise. I thought it was either my pump/alternator belt, or maybe the fan, but after removing both and running the engine for 20 seconds (and taking this video) I'm positive it has to be something else.

Timing belt or bearing? I can't tell if it's coming from the top or bottom of the engine, but I can tell it's coming from the front, and that it's vertically inline with the crank and cam shafts.



Of note, this recording loses a tiny bit of the high pitched sound. In other words, in the recording it sounds more mechanical... though I suppose not much.

I noticed this sound starting about... 30-60 miles ago, give or take 20
It usually made it on start up, and then wasn't there by the time I rolled into my destination. This is why I originally thought it was a belt. It was only ever audible at idle. The last time I arrive home, I realized it was still making the noise, and it was at this point I parked it until today.

What do you guys think?

[Northern]

A friend's car was doing something similar, and the timing belt was rubbing against the timing cover and fraying. Not sure if this is the same issue, but it was very obvious once you saw the belt.

[Earendil]

A friend's car was doing something similar, and the timing belt was rubbing against the timing cover and fraying. Not sure if this is the same issue, but it was very obvious once you saw the belt.

Thanks. That might be worth checking out. At the very least it gives me something to do to diagnose further. I wasn't sure how I was going to identify a noisy timing belt without the engine running. But if it is hitting the timing cover, that should be obvious.

[Earendil]

You nailed it! At least I hope you did, otherwise I have two problems. Here is what the timing belt looks like with the cap and rotor removed. Notice all the black "dust"


HQ Version

So now the stupid question is, can I just shove it on and keep driving? I just replaced the timing belt, water pump, and pulley this winter. It can't have more than 500 miles on it.

Second question (and the more sane one) what causes a timing belt to shove out like that?

[SpecM]

take the covers off to check. maybe misaligned tensioner, maybe play in the intermediate shaft

[dnguyen1963]

I would not drive that car anywhere until the problem is fixed.

[Earendil]

take the covers off to check. maybe misaligned tensioner, maybe play in the intermediate shaft

With the number of timing belt changes I've done, I'm not sure why that didn't occure to me. Call it Friday brain.

The tensioner was indeed loose. Loose enough to be "dumping" the belt into the timing belt cover. It even carved a little groove the entire length of the cover :shock:

I would not drive that car anywhere until the problem is fixed.

You're only the 4th person in the third area of my life to misunderstand me today. Apparently I'm not doing well on the communication front. I was not suggesting that I drive it without fixing the problem, only wondering if once the source of the problem was fixed, whether the timing belt was a secondary problem. I measured the width of my timing belt at 22.2mm, and did that with the intention of asking if anyone had a spare they could measure.

However, after seeing the carved out metal cover, and eye balling the belt, I figure it's probably toast. I've ordered a new one and will just have to replace it again *sigh*

Thanks everyone for the help. In retrospect I could have just taken the cover off and seen this all for myself, but I was caught up fearing it was a bearing and that sound was going to be my only clue. And Friday-brain.

Thanks guys :)

[dougie30]

dude please dont drive with that timing belt....

[jlevie]

Any damage to a timing belt is cause to replace it. And one that has been used much at all should not be reinstalled. You don't take chances with a timing belt and/or tensioner.

[Earendil]

I've ordered a new one and will just have to replace it again *sigh*

dude please dont drive with that timing belt....

Any damage to a timing belt is cause to replace it. And one that has been used much at all should not be reinstalled. You don't take chances with a timing belt and/or tensioner.

I have not yet taken the belt off yet, and if it had only been "minor rubbing" with no perceptible damage to the belt, I might have driven on and kept a close eye on it. However there is damage, and It will be replaced. Thanks guys for backing up my conclusion!


Bonus pictures for sticking around, and to see what an M20 timing belt can do to an aluminum timing belt cover. I'll have to measure the new belt, and meaure the depth of the groove and see which side officially won the friction/abrasion contest.