Hey folks. I have a strange noise coming from my engine bay. This is after I just rebuilt the engine. It seems to be getting louder by the day. It's a slow rythmic grinding or rubbing but I can't tell if it's metal or something else. Anyway, using a screwdriver I was able to narrow it down to the psgr side of the timing belt area. There is no question in my mind it coming from the timing belt area and not the heads. The noise is only transmitted through a screwdriver when placed to my ear when I put it on the timing belt cover. Nowhere else. I captured a video for you to have a listen to:

YouTube - Yet another odd noise

So folks, is this what a bad idler pulley or camshaft sprocket bearing sounds like? It is only really noticeable at idle and used to go away when the car warmed up but now it seems to be there all the time at idle. It does go away when some load is placed on the engine though. The other thing I was thinking it could be was a bad tensioner that is causing the belt to kinda rub or slap on the cover somewhere. I also notice some belt whine when engine is cold. By the way, I put an STI timing belt on the car.

Any help is greatly appreciated. Thanks in advance, JC

EDIT: I was just out driving some more and it's weird... I can hear it well after the car is warm so long as I haven't gone above 3000rpm. And the grinding or rubbing gets a little faster (but fainter) sounding as I accelerate and then vice versa as I decelerate. However, after putting a little load through the engine, I notice that the sound pretty much goes away, even at idle. I go into the mall for a bit, maybe an hour, come back out and the noise is there again. Stays for a while but then when I get on it, it goes away again. Very strange. Again, I am positive this is coming from the psgr side of the timing belt area but can't tell if it's top or bottom. This makes me nervous because there is no idler in that area... meaning, I wonder if the cam is somehow grinding in the journal or something? That would be bad, very bad.

 

Sorry Mods, you'll probably want to move this to General Technical.

 

Bump for some advice...

 

Were the idlers checked before the final build was complete? or did you use new idlers?

I had a similar noise recently, but less grinding, more of a knock and very similar symptons. This i pin pointed to the cambelt tensioner. I replaced the tensioner and all has been fine.

I would suggest that you remove the cambelt and check each of the idlers and the tensioner, and replace where applicable.

 

Thanks for the reply. I reused everything but now have a new tensioner on the way. I hope that is the issue. My idlers all seemed fine so didn't bother to replace them. I am not sure why they would have bee fine before the build but not after. Regardless, I think it must be something to do with the idlers or tensioner so this time around I may go all new.

 

Took off the psgr side cam cover tonight to have a peek. It looks like something was rubbing on the belt. Not sure what... I know it is not the upper pulley guide so it must be the lower one. Funny thing is though the marks on the timing belt look wider than the pulley guides themselves, indicating a possible rubbing on the cam cover itself... perhaps somewhere along the bottom?



What I don't understand is why the noise goes away after the car gets nice and warm. Meaning, it seems to go away once the rpms get up for a bit... enough tot sufficiently heat up the belt and the idlers/bearings. Do the idler bearings expand with the heat perhaps? Or, maybe the belt contracts? I know I have heard of bad tensioners making cold start noise that goes away when warmed up... could this be related?

 

Oh, your passenger side is different to ours

Looking at that scoring i would suggest it could well be the CRANK belt guide thats doing that. Perhaps it is sat loose, and then as the idlers and belt warm up it becomes tight, stops rattling but scores the belt instead.

Strip the cambelt arrangement down, and thoroughly check everything.

 

Oh right, forgot about that wee little difference.