44 replies to this topic

[flaco]

I've tried to find a 'rubbing' noise during cold startups. Sounds like one of the timing pulleys is rubbing against the plastic covers. Noise goes away after 30-60 seconds of driving. Noise is rpm dependant: it gets louder with rpm. Noise is not present on warm/hot starts.

The following have been discarded as a cause of the noise:
PS/alternator/AC/acc belt: removed the acc belt one morning, and then started the engine, noise was still present.

timing pulleys/belt/water pump/tensioner: Just replaced those ~2 weeks ago, noise still present.

turbo: started engine with intake hose removed while I was holding the turbo compressor wheel with my hand, noise still present.

transmision/clutch: replaced clutch&bearing ~ 2 months ago. Noise does not change when in neutral, clutch in/out, in gear, car moving, etc.

Any other ideas what might be the cause? It sounds reaaaly awful in the mornings, it feels like something is about to break!

[AlvinL]

I found a wierd noise too when cold but goes away after a few minutes of driving and warming up. Turns out a broken hanger rubber strap for the suitcase muffler left the exhaust system lower and knocking against a metal support. Glad I caught it sooner than later cause that is not good for the exhaust to be strssed like that.

Keep looking and good luck.

[flaco]

Thanks, I'll try to get a sound clip and post it here...

[flaco]

here we go:

[Austin H]

Mine makes the same noise. Timing belt and all tensioner replaced, still made the noise I took it in and they said all my belts and everything were just fine. Will the SAS air pump make that noise? I think I read somewhere that will be noisy on cold startups but I don't think it should be RPM dependent.

[flaco]

yep, also tried to diagnose that by unplugging the pump relay, and disconnecting the sas valve vacuum line, and still got the same noise!

[--Aaron--]

From the inside of the car it would sound as if you were housing an elephant under the hood.

Sounds like a beehive from under the hood......

Remove your timing belt cover (outer portion), be sure it's installed correctly and be sure you reassemble correctly. Also, remember that half moon metal bracket thing that you had to unbolt and remove to do your timing belt? Of course you do because it is a pain in the ass. Check and be sure that's not skimming the belt as it rounds the crank pulley.

That's all I got.

[flaco]

--Aaron--, on 14 April 2010 - 12:24 PM, said:

From the inside of the car it would sound as if you were housing an elephant under the hood.

Sounds like a beehive from under the hood......

Remove your timing belt cover (outer portion), be sure it's installed correctly and be sure you reassemble correctly. Also, remember that half moon metal bracket thing that you had to unbolt and remove to do your timing belt? Of course you do because it is a pain in the ALL GLORY TO THE HYPNOTOAD. Check and be sure that's not skimming the belt as it rounds the crank pulley.

That's all I got.

Yep, did all that with the prev belt. Changed everything because I thought there was something wrong with the old pulleys etc. Since I changed everything, noise remains unchanged. Ive ran the engine without the cover both w/ old and new belts and everything looks fine, and noise is still there...

[--Aaron--]

What about that half moon cover over the crank pulley down below? Is that there? Is it installed correctly?

[64pvolvo1800]

flaco, on 14 April 2010 - 02:00 PM, said:

Yep, did all that with the prev belt. Changed everything because I thought there was something wrong with the old pulleys etc. Since I changed everything, noise remains unchanged. Ive ran the engine without the cover both w/ old and new belts and everything looks fine, and noise is still there...

1) cold start, run a few minutes with the cover off.
2) once the squeal starts and runs a few, shut it off.
3) immediately compare the temperatures of the timing pulleys to find the culprit.
My 98 S70M did this and it turned out to be the idler pulley on the timing belt. I know you said they are all replaced but were they blue box?

[flaco]

Half moon was and it's still there. Back of the old belt is unharmed, new belt still looks new.

And yes, all pulleys (idler, tensioner, water pump and hydraulic) were replaced with blue box stuff from DW.

[64pvolvo1800]

flaco, on 14 April 2010 - 02:51 PM, said:

Half moon was and it's still there. Back of the old belt is unharmed, new belt still looks new.

And yes, all pulleys (idler, tensioner, water pump and hydraulic) were replaced with blue box stuff from DW.

Maybe your squirrel just took up tuba lessons and he's practicing

[Austin H]

I seriously want to know what this is. It only happens for about two minutes on a cold start. Everything checks to be in good working order on my car. Though if I start my car cold and shut it off after a minute, let it sit for 10 sec and restart it, there is no noise.

I'm just going to go with my car is yawning after a long night of sleep until I figure out otherwise. Flaco keep us posted and I'll do the same.

[Dave 54]

Have you tried to remove the serp. belt and start the car to see if the noise is still present?

[Austin H]

flaco, on 12 April 2010 - 01:19 AM, said:

The following have been discarded as a cause of the noise:
PS/alternator/AC/acc belt: removed the acc belt one morning, and then started the engine, noise was still present. 

I've done the same.

[flaco]

Austin H, on 15 April 2010 - 12:10 PM, said:

I seriously want to know what this is. It only happens for about two minutes on a cold start. Everything checks to be in good working order on my car. Though if I start my car cold and shut it off after a minute, let it sit for 10 sec and restart it, there is no noise.

I'm just going to go with my car is yawning after a long night of sleep until I figure out otherwise. Flaco keep us posted and I'll do the same.

Yep, same here...

It is WEIRD...

[jablackburn]

Flywheel bearing? Only seen it happen ONCE before, but it did sound something like that.

[flaco]

jablackburn, on 15 April 2010 - 06:13 PM, said:

Flywheel bearing? Only seen it happen ONCE before, but it did sound something like that.

Interesting idea... I didn't change the bearing inside the crankshaft end. From what I saw, the trans input shaft doesn't go that far anyway.

I'd think that if the clutch pedal is out, it shouldn't make any noise. The crank and input shaft are turning at the same speed. The noise doesn't change when I press the clutch either, which should reveal if that bearing/bushing is the culprit.

Seems we're out of ideas LOL

[Austin H]

A little far fetched maybe but could it be our Turbo? Mine doesn't leak, holds boost but I don't know maybe it could be going bad. I'll stick my head at the back of my engine next cold start.

[64pvolvo1800]

Austin H, on 15 April 2010 - 10:17 PM, said:

A little far fetched maybe but could it be our Turbo? Mine doesn't leak, holds boost but I don't know maybe it could be going bad. I'll stick my head at the back of my engine next cold start.

NOPE, see post #1