Squealing, 96 Bonnie, not a Newbie question(again) - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

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Old 05-26-2006, 04:41 PM   #1
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Default Squealing, 96 Bonnie, not a Newbie question(again)

I am working on my friends car again and having a problem. This was the problem last time:

http://www.bonnevilleclub.com/forum/...ic.php?t=53349

Here is some quick history: (it’* the L36)

Several months ago the FPR was leaking and caused a upper intake manifold failure (catastrophic), My friend took it to the local mechanic to replace the upper and some related parts. I have never trusted since he does a half-assed job most of the time, and sucks at trouble shooting. Anyway this time after several weeks there was a squeal that only happens at idle and only after a few minutes of idling.

And now the rest of the story:

The sound is from both the front and rear of the engine and is next to impossible to locate even with a stethoscope. I thought it was the idler and told Mauro to replace it. He did and still had the problem, it sounded as though the alternator bearings might be bad, and since he had a brand spanking new one we replaced it. After replacing it the sound “went away”. My bosses son bought the car and he was going to pick up the car but ha and Mauro heard a noise. I found I had screwed up and installed the belt one tooth off on the AC compressor (after telling my boss what a pain it was to make sure the belt was aligned on the crank pulley). This ruined the belt so I said if you get a new belt I will help him replace it. Yesterday they came in with the belt and we installed it (who came up with having to remove that stupid spacer ought to be flogged). All was well and he was set to drive it home, but after moving it out of the shop and around to the front as they were leaving it started squealing so it was parked. This morning my boss asked me to take a look at and see what I could find.

After starting it and about 3-4 minutes I started kicking it in and out of gear and turning on and off the AC it started making the noise again. I started poking around and could not locate the noise other than on either the crank ends of the engine seemed to emit this squeal. If you rev it up it goes away. I removed the belt and started it again within 10 seconds it came back and sounded like it was coming straight from the balancer (damper) area and still at the rear of the engine. Now I am thinking it’* a spun bearing except it goes away. Then I start to remove the engine cover with the engine running to see what I can figure out. I start to remove the oil cap and someone is pulling on it from the inside, the vacuum was tremendous. As I remove it air rushes in and the engine stumbles the squeal goes away and the engine recovers back to idle (stumble caused by unmetered air entering the system?).

The noise seems to be caused by air entering the front and (or) rear main seals, and is either a whistle or squealing because of the oil being drawn off the bearing surface at idle (when oil pressure is lower).

I cannot tell how the PCV system works, I am used to seeing a place on both valve covers, one for the PCV and the other for filtered air to enter the engine. It seems to me that the problem is the filtered air location is blocked causing this problem. My question is where and how is the system routed?

Thanks

Jeff
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Old 05-26-2006, 07:14 PM   #2
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Old 05-27-2006, 09:42 AM   #3
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I just went through THE SAME THING.

http://www.bonnevilleclub.com/forum/...ic.php?t=54804

Read page 2.

You probably missed the small o-ring under the PCV valve. My noise was EXACTLY the same. It was loud!. I had to install the o-ring, and remove and reinstall the upper intake, as the gasket had come unseated, and would not reseat by just tightening the bolts. There was also some oil pulling into the lower intake that needed to be cleaned. When it'* running, spray some carb cleaner, or starting fluid like I did, around the upper to lower intake gasket. The idle will increase when it sucks some fluid in where it'* leaking.
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Old 05-27-2006, 10:18 AM   #4
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That is exactly the problem. And it'* quite common. One little PCV o-ring. At least it'* an easy fix, right?
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Old 05-27-2006, 10:29 AM   #5
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Could this be my problem as well?
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Old 05-27-2006, 10:39 AM   #6
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Not as likely. But in your case, we'll have a better idea after you drive without a belt to further isolate the problem.

Pull your oil fill cap while idling. Put your hand over the hole. Notice anything odd?
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Old 05-27-2006, 11:37 AM   #7
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Quote:
Originally Posted by willwren
Pull your oil fill cap while idling. Put your hand over the hole. Notice anything odd?
Mine tried to suck my hand into the valve cover. :o
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Old 05-27-2006, 02:19 PM   #8
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Well like I said this was taken to a hack mechanic when the upper intake grenaded. I should have known that something like this would happen. Is the o-ring(*) available separate? Since I didn’t do the work I don’t have any of the parts that came with the new manifold/gasket set. I guess I can get new ones if I buy a PVC valve. My boss is supposed to bring the Chilton on Tuesday so I can take a look at the diagram.

So what exactly causes all the noise? I understand what is happening air is being drawn out of the crankcase and no air is being allowed in so the crankcase ends up being under tremendous vacuum; air is being drawn in through somewhere but is it really the front main seal Rear main seal or what?

Thanks Guy’*

Jeff
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Old 05-27-2006, 03:40 PM   #9
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What exactly did the Hack mechanic supposedly do?

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Old 05-27-2006, 04:22 PM   #10
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Default Re: Squealing, 96 Bonnie, not a Newbie question(again)

Quote:
Originally Posted by J57ltr

Several months ago the FPR was leaking and caused a upper intake manifold failure (catastrophic), My friend took it to the local mechanic to replace the upper and some related parts. I have never trusted since he does a half-assed job most of the time, and sucks at trouble shooting. Anyway this time after several weeks there was a squeal that only happens at idle and only after a few minutes of idling.
He left the Oring out or didn't install it properly if that is the case. I can think of several things that I have had to go behind him and repair and, based on previous history (crossthreading bolts, leaving off brackets, Inabality to diagnos simple problems, mixing Dex-cool and regular anti freeze on this car and our shop truck), I am pretty sure that when I get in there on Tuesday I will find that the problem is that he left the O-ring out.

Jeff
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