Randomish Squeal

[waffles]

Hey gents, so my 3.2 is all built up and swapped, I have about 700 miles on her and it makes excellent power. Anyway I have a small issue. Whenever I clutch in and kick the gas for a downshift I hear a squeal as the revs climb. My 3.0 did this too, is it a transmission issue? I'm pretty confident it's not the motor, just because it made the noise with the 3.0 in too. Could it be an accessory? The main bearings were good and in spec, and the rod bearings have been replaced and were checked to be in spec. Ideas?

 

[rubydist]

depending upon what kind of squeal it is, it could be a loose accessory belt slipping when you quickly rev the engine, a throw out bearing squeal, a dry bearing on one of the idlers, etc.

can you replicate it sitting in the driveway? or does the car have to be moving?

 

[AREA 91]

My guess would be from the accessories.
Tensioners, A/C clutch, etc...

 

[Storm-Chaser]

Remove the blonde from the right seat...


:thankyou:

 

[waffles]

Remove the blonde from the right seat...


:thankyou:

That's not an easy fix, I can't find it in the service manual anywhere! Does this repair have the added benefit of weight reduction?

 

[Storm-Chaser]

Yes, with one exception.

Weight reduction for the anorexic model is negligible...

 

[Storm-Chaser]

In all seriousness...

Most likely it is a belt slipping. The question is "why"? Is it the belt - the tensioner tension - an accessory.

While it may be a tensioner, you can usually replicate that while the car not moving (i.e. not under a load).

The fact that it is occurring only when the car is under a heavy load situation (rapid acceleration) leads me to think is is a bearing - such as an alternator/compressor/tensioner/power steering pump/water pump internal bearing that is not making a noise [yet], but is creating enough friction that results in the belt slipping because the bearing cannot itself accelerate fast enough due to the internal friction (and at some point - versus the bearing locking-up due to the heavy load that is temporarily being placed on it, just before the belt snaps).

You can use the "stethoscope" method of using a long screwdriver grounded against a non-moving part of the suspected accessories, and the plastic handle end placed against your ear to find a "noisy" bearing that hasn't become noisy enough to be heard over the engine noise.

OTC, Lisle, and other tool manufacturers actually make a "mechanics stethoscope" that you can buy. And yes, Harbor Freight even carries their 'lasts for a few uses' version of a mechanics stethoscope.