Squeeling noise but not the belts...

**mac2444** · #1 (**permalink**) 08-31-2009, 11:39 AM

Hi All,

I'm totally stumped. I bought a 91 164L a couple of weeks ago and just put it on the road after the usual tune up work etc. It's making a squealing noise whenever I push the gas in hard or let it off completely while in gear. It sounds just like belt squeal so I went over the belts one by one alt, Serpentine, ps. I have even run the car after removing each belt and the noise is still there! I've never heard anything similar on my GTV6. Any ideas??
The timing tensioner also seems fine, still fresh grease in the bearing, no play. It's hard to tell but it almost sounds like the noise is coming from the lower rear of the engine.

Any suggestions are much appreciated.

Thanks

**ChazzyD** · #2 (**permalink**) 08-31-2009, 12:33 PM

manual trans car?
Charles

**mac2444** · #3 (**permalink**) 08-31-2009, 01:46 PM

Hi, yes it's manual. I just went for another drive and the noise is almost more of a hiss or whine than a squeal (not that this will help much) but it's really evident with the windows down, loudest when coasting with my foot off the gas goes away if I'm at partial throttle and comes back when I accelerate. Same noise in all gears, it changes pitch with the engine rpm.

**ChazzyD** · #4 (**permalink**) 08-31-2009, 02:17 PM

So, not a throwout bearing, doesn't make the noise when you push in the clutch pedal? If it makes a noise in gear with the clutch engaged, and changes with engine RPM, it could be an internal tranny bearing, like an input shaft bearing. If it sounds like a box full of rocks leaving a light in first and then in second, etc, or makes harsh whining noises under heavy acceleration, than it's the input shaft bearing. Hard to say without hearing it and experiencing it. If you suspect an input shaft bearing or a diff pin problem, do not keep driving it or it will destroy itself and be un-rebuildable (don't do what I did).

Charles

**mac2444** · #5 (**permalink**) 08-31-2009, 02:24 PM

Thanks for the input Charles. It may be something to do with the cluch but I'm not sure. The noise does happen when I put the cluch in and rev the engine but it's not nearly as loud as when the cluch is out and I'm coasting. The imput shaft bearing sounds possible, there's no box of rocks or anything but the rpm would match the sounds if that were the culprit. I was rally hoping not to have to pull the tranny before next summer but I guess I may have no choice. If that bearing fails I'm guessing I'll be in a world of hurt.

**alfasrule** · #6 (**permalink**) 08-31-2009, 05:13 PM

Common problem with this car. If it's never been changed it' probably the culprit

AlexGS · #7 (**permalink**) 08-31-2009, 06:21 PM

I think it would be unusual for a transmission input shaft bearing to make a belt-squeal type of noise. It is oiled, after all. A box-of-rocks noise is much more likely from that.

Therefore I wonder if you have a vacuum leak under one of the chrome runners (bolt stripped or cross-threaded?) or where the intake manifold bolts to a cylinder head. That would tally with the noise being highest under over-run/coasting (when manifold vacuum is highest), going away with partial load, and coming back again at full load.

A leak between metal components produces a whistle in my experience but I guess you could be even luckier and find a split under the intake corrugated rubber hose.

-Alex

**mac2444** · #8 (**permalink**) 08-31-2009, 07:19 PM

Thanks for your input guys, Alex that does make a lot os sense and better yet it keeps my car in one piece while I figure it out

I'm sure the tranny bearing is tired too, the cluch is starting to feel a bit rough so I'm assuming it hasen't bee apart in a long time. Aside from that thought the car is in amazing shape.

Thanks again, I'll keep you posted on what I find.

Graeme

**ChazzyD** · #9 (**permalink**) 08-31-2009, 07:33 PM

If it sounds like belt squeal, than I doubt it is an internal bearing either. Maybe a random stray bolt rubbing on the flywheel or clutch? I'm grasping at straws now, because nothing is making good sense. If the clutch needs replaced, you will probably find the answer... when you get it apart, unfortunately. It will be worth the effort if the car is nice besides this little problem.

Charles

Michael Smith · #10 (**permalink**) 08-31-2009, 08:16 PM

Failed input shaft tranny bearing makes a clicking sound (tick tick tick).

Squeal is either belts or bearings.

Very likely culprit is the AC compressor pulley. The AC uses separate V Belt from the serpentine belt that runs everything else.

Another possibility is the tensioner for teh serpentine belt or MUCH worse the tensioner for the T Belt. When was the T Belt last replaced?

**mac2444** · #11 (**permalink**) 08-31-2009, 11:41 PM

It's not the belts or the tensioners, I've run the car without the belts on it and the noise is still there ( tried to run it without the timing belt but it wouldn't start??

) . I sat there beside the tensioners and can be sure they wern't the issue either. I'll do a little more digging this week and see if I can't figure it out, a vacuum leak would fit the profile nicely but I've just never run into one that loud before.

**jeffb99tx** · #12 (**permalink**) 09-01-2009, 06:21 AM

Have you checked the condition of your motor and transmission mounts? If one of those is failing, it can cause shifting in the engine under torque load. Just a thought...

Jeff
Dallas, Texas

**ChazzyD** · #13 (**permalink**) 09-01-2009, 07:06 AM

Quote:

Originally Posted by mac2444

( tried to run it without the timing belt but it wouldn't start??

).

Michael Smith · #14 (**permalink**) 09-01-2009, 10:41 PM

One place for a vacuum leak is the rubber intake bellows. Carefully check all around the corrugations. Another is the foam insulator around the automatic idle control circuit where it joins the intake plenum.

**mac2444** · #15 (**permalink**) 09-03-2009, 10:47 AM

Well, it's not a vacuum leak, the motor mounts all seem good, so I think I'm back to the cluch/tranny bearing. I've taken it out on the road a bit and the noise has to be some kind of belt or bearing "whine". The cluch chatters a fair bit as it is so I don't really mind pulling it, I was planning on doing it in the spring anyways. Now I'm off to order some parts....