Buick Riviera 1966, squealing noise

C

Cileb

Member
Buick Riviera 1966

Could anyone have a real idea what might be causing this squealing noise? It can be heard from 00:25 and even better from 00:40. I’ve been trying to figure out where it’s coming from for months. It’s audible at idle and when the engine is under load (driving or while stationary). However, once the car is coasting on the road without applying throttle, the squealing stops.

It seems to be heard more from beside and underneath the car, and especially from the driver’s seat. When standing in front of the engine, it’s not noticeable. I’ve driven about 300 miles with this issue, and it’s always the same. The mechanic I took it to charged me without fixing the problem, and now I have to take it back to him. He says the exhaust mufflers might be the cause because they’re made of stainless steel, but that doesn’t really make sense to me. They’ve always been the same, and no one has touched them.

VID 20260509 153544 : Free Download, Borrow, and Streaming : Internet Archive

Does anyone have any idea what it could be? This drives me crazy.
 
Squeaks can be impossible to find. I remember once an friend stopped by and was complaining about a squeak that they had taken their car in to a couple of garages including the GM dealer, and no-one could find the squeak. After only a moment of looking I noticed a very small piece of gravel, I think it was wedged between the exhaust manifold and a spark plug guard. We picked it out, and the squeak was gone. It was just luck that solved the problem.

I had a divers door squeak on a my truck, eventually I had a reason to pull the door apart and found a screw that was not properly tightened or at least had loosened at some time.

Not much help, but a squeak can be hard to find, or the fix can fall into your lap.
 
If it's not belts (easy to find, squirt them and if the squeak goes away, bingo), maybe it's exhaust hangers, something in the exhaust (flanges), something dragging across the exhaust (e-brake cable)...

If you shove on stuff while it's running...exhaust pipes, trans mounts, cables, etc... maybe you can find it.

Had a friend with a cracked exhaust manifold shield that sounded like his engine was coming apart. Added a fender washer under the shield, silence. Sounds can be maddening.

All of this is easier on a lift. You'd think your mechanic could've zeroed in, but...like I said, sounds can be maddening!
 
from listening to your posted video, it sounds to me like multiple exhaust leaks at the engine and further back. also, from what saw from the panning of the camera on the underneath looks like those muffler inlets are bigger than the pipes and appear to have a load weld making up the size difference. i would look that system over with a fine-tooth comb. i have seen this before. hope this suggestion helps. good luck.
 
It sounds like a belt system noise transmitting through the engine. I'd start by pulling off the belts and checking the alternator, waterpump and power steering bearings for a squeal. Since it's strong underneath it can also be from the transmission or perhaps the flywheel. But I'd start with the belt system bearings. If it's the wrong application Buick water pump or improperly rebuilt it could be rubbing the timing cover behind it. If nothing else run it for a minute without the belts, if no noise that will give you a direction to go in.
 
Thank you guys for your suggestions. (y)

It seems the problem is in the exhaust mufflers. I took the car to a mechanic and then to an exhaust specialist. Both of them said the noise was coming from the two mufflers located directly underneath the front seats, with the left one being slightly louder than the right. They were right. Once we were able to get underneath the car, I could clearly hear that the damn squealing was coming from there.

Interestingly, the squealing became much quieter after about 25 minutes of normal highway driving at a constant throttle. It seems that once the exhaust is fully warmed up, or when there's a steady flow of exhaust gases, the noise becomes less noticeable.

The mufflers are made of stainless steel, and from the outside they look to be in good condition. The exhaust pipes, however, had been poorly repaired previously. Apparently, somebody didn't have pipe of the correct diameter, so he patched it using smaller-diameter sections. The pipes in front of the mufflers have now been replaced with the correct diameter throughout, but the pipes behind the mufflers were left untouched because the mechanic apparently didn't realize I wanted those repaired as well. In any case, replacing the front pipes made no difference at all to the squealing.

I've heard that stainless steel mufflers can sometimes ring or resonate, but not to this extent.
It looks like I'll end up replacing the entire exhaust system because this squealing is driving me crazy. But..... what on earth can happen inside a mufflers that makes it squeal like this??
 
i would install the correct style mufflers and the correct pipe on the rest of the system. ask for the mufflers back and open them up with a Sawzall and you may see something but i think it's just the metal and they could be cheap quality mufflers. i had a system made for my 70 lesabre by Waldrons exhaust. i put it on and fit perfect with no issues and sounds factory. good luck
 
Cileb said:
Buick Riviera 1966

Could anyone have a real idea what might be causing this squealing noise? It can be heard from 00:25 and even better from 00:40. I’ve been trying to figure out where it’s coming from for months. It’s audible at idle and when the engine is under load (driving or while stationary). However, once the car is coasting on the road without applying throttle, the squealing stops.

It seems to be heard more from beside and underneath the car, and especially from the driver’s seat. When standing in front of the engine, it’s not noticeable. I’ve driven about 300 miles with this issue, and it’s always the same. The mechanic I took it to charged me without fixing the problem, and now I have to take it back to him. He says the exhaust mufflers might be the cause because they’re made of stainless steel, but that doesn’t really make sense to me. They’ve always been the same, and no one has touched them.

VID 20260509 153544 : Free Download, Borrow, and Streaming : Internet Archive

Does anyone have any idea what it could be? This drives me crazy.
Click to expand...
Youve paid mechanic and he accepted payment to fix your squeal noise, entered into contract. The mechanic should be trying to find your noise. Take the car back, cant see why you are trying to fix someone elses responsibility. Be aware sometimes people will tell you things to get rid of you. Your mechanic should have an electronic chassis ear($50), picoscope, or chassis ear to find your noise, and show you its the e haust as they state. Take it someone that does have tools and ask for refund.
 
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