So I've been trying to figure this one out for a bit.

Had what I thought was a belt squeal, but now im not so sure. The squeal only comes about when the car is in gear and at any speed above idle. It does not squeal if it's in park or neutral and I rev the engine.

Have a timing belt kit i plan to do soon, but still havent figured out whats causing the squeal...belt seems fine, tensioner seems fine, alternator is working, no power steering issues and the A/C is nice and cold. All pulleys seem fine and no wobbles seen while running it.

recent replacements are the alternator, belt tensioner, and crank pulley, all of which needed to be changed.

Any ideas?

 

Does it change with engine speed or road speed?

Load or overrun?

You could try shifting into N when cruising and see if that makes a difference. Not for too long though - transmission oil pump...

 

the only real change is when it drops down to idle, and only when it's under load, it doesnt change at speed however, so if you let off the gas it doesnt change pitch at all, which is what first led me to believe it wasnt the serpentine...are you saying it might be the transmission oil pump and if so, how difficult is that to access and change out?

 

No - I'm saying don't cruise in neutral too long or you'll damage the transmission.

I was trying to establish if it's driveline related or engine-related. I understand the propshaft centre bearing can get squealy on these.

If it's purely engine load-related, it could be a vacuum leak or something causing a whistle.

Wetting the serpentine is the best way to establish if it's slipping.

I've had a screechy tensioner pulley of an S2000 (only at yo-VTEC! speeds) rapidly identified by squirting WD40 into the bearing and it went away and similar with an a/c clutch on a Civic. Squirt of WD40 seemed to result in a permanent fix...

I suppose you could always remove the serpentine and briefly(!) drive to see if that eliminates all those items. Steering might be a tad heavy, if yours is hydraulic like mine.

 

Seems like you might be right with the driveshaft center bearing. In addition to the noisy squealing there has been increased vibration and I just replaced all the motor mounts, had the wheels rebalanced and a fresh alignment which didn't fix that problem.

 

My center driveshaft bearing makes the little whine around 30 mph. It would be worth getting the car on a lift and listen to that bearing with it spinning at different speeds. I haven't heard of anyone being able to repair that bearing but there are some very competent driveshaft shops. It would be great if some shop would figure out the repair. They would certainly get plenty of work that that skill set.

 

would get very expensive if the driveshafts had to be replaced as they are carbon fiber and custom for the car...

 

Yes, the cost of a new propshaft probably trashes the car.

If there's a way of re-lubing it, then fine. If there's play or seizing, you're in trouble.

 

keeps squealing if you put it in neutral on the freeway...

 

OK - that reasonably eliminates the lump.

Check it's not something really daft like the anti-chatter springs on the brake pads (or a trapped stone!) before getting depressed. If it goes away under braking, you might be in luck!

 

could be a trapped stone since I go to work on a dirt road, but it doesnt go away when braking...im wondering if the used crank pulley i replaced is the culprit. The old one had the rubber material separated and due to the wait on shipping for a new one I had to scavenge one from a Honda oddyssey. I do have one of those lightweight crank pulleys available but haven't gotten around to putting it on...

 

I'd have thought you'd get a change in note with RPM. But it's seconds to stick you finger in the crank pulley to verify.

Do it before it has a chance to lunch the timing cover & jump the belt...Hondas are notorious for that, even if many deny it.

 

I had a thought - there used to be prop shops who would customise or rebuild propshafts; maybe they could make you a steel one, utilising the bearing carrier and I dunno, GM bits?

Might be worth an ask.

 

My harmonic balancer would squeal when the AC came on back when I first bought mine used a few years ago. The rubber between the putter/groove ring was cracked and under that extra load it would slip. New balancer did the trick. If it’s not that, maybe the serpentine tensioner is bad.

 

Theres a typo I didn’t catch. Putter/groove should be outer/groove ring. Anyway, here is a video I took of mine way back when.