UPDATE - Whirring noise from front cover area - Page 3 - 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 05-25-2006, 07:41 PM   #21
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Well, I hate to admit it, but I was way off on this one. Fortunately, I let another tech listen to the noise, and he thought the same thing I did. I made a discovery that it it NOT trans related, but engine related. This whirring sound has something to do with vacuum, as in the PCV system, or a valve leak somewhere, or SOMETHING. We determined this by doing a simple test that I wish I would have thought of: Taking the oil fill cap off with the engine running. When you do, the noise goes away. I also notices that there'* a vacuum being pulled on the oil fill opening on the valve cover. It had a new PCV installed when I did the UIM/head work about 1500 miles ago, and it still seems to be OK. I've rechecked all the connections, and everything appears to be connected correctly (I have an FSM and a Chilton book). Any ideas? I would have bet money on a rotational noise (bearing, torque converter, etc), but it most definitely is not. Help!
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Old 05-25-2006, 07:47 PM   #22
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You missed an o-ring in your PCV valve.
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Old 05-25-2006, 11:03 PM   #23
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GIVE THAT MAN A CIGAR! Thanks! Since I'm a needy guy, I need some more help. After getting that straight, the car idles like it has a miss, AND it'* throwing a CEL. The code is for MAP sensor reading high. My question is do you think this miss was there all along, and the PCV leak covered it up, or is this a two-part problem? It'* weird that although it made the most hellacious whirring noise before, it ran great. Jeez, what next?

PS: There is no spring in the PCV cover thingy. On my '97 SE, should there be?
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Old 05-25-2006, 11:29 PM   #24
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No spring for you!
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Old 05-25-2006, 11:48 PM   #25
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Quote:
Originally Posted by popatim
No spring for you!
Thank you, PCV ****!

Now I wonder why it runs like crap at idle? I wonder if I compromised the intake gaskets running it like this? What other possibilities? It doesn't leak any oil - I know that the crank gaskets can give way under this condition.
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Old 05-25-2006, 11:57 PM   #26
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Did it change when you installed the O-ring? If so, I'd suggest replacing your PCV valve and checking for vacuum leaks. Spray a small amount of carb cleaner around the PCV cover at idle and listen for the idle to change. Check all other vacuum fittings in the same manner.

A vacuum leak will suck in the solvent and combust it, changing the sound of the idle.

It may also be as simple as letting it go for a few days. With the O-ring missing, the pressures were higher in the manifold because the crankcase was constantly venting around the PCV valve. The PCM may have learned this as 'normal'. Now you've fixed that, and the pressure has dropped.

On the flip side, if the PCV valve is stuck, you were allowing it to vent by with the o-ring missing, but now have fixed the 'bypass', and really freaked it out.

I dunno.....Neither of my cars use the MAP sensor for anything PCM related. My 93 only has one for a boost indication, and the 95 doesn't have one at all.
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Old 05-26-2006, 12:04 AM   #27
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Quote:
Originally Posted by willwren
Did it change when you installed the O-ring? If so, I'd suggest replacing your PCV valve and checking for vacuum leaks.
Yes, there'* no more suction from the oil filler at all. The PCV valve was new when I did the UIM, and appears to be working right. I figure, too, that it'* a vacuum leak caused by all of the sucking in that it was doing under the no o-ring condition. At idle, it definitely sounds like a miss. I drove it around the block, and when under a load, it seems to run right, or close to it. The idle has that sputter at the exhaust, and the engine shakes just like having an ignition miss.
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Old 05-26-2006, 12:10 AM   #28
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Yep, I just sprayed starting fluid around both the PCV cap thingy, and around the upper intake gasket. Both times, the engine revved up slightly. Well, at least that'* a relatively easy fix. Would you think that the LIM gasket could be messed up too?
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Old 05-26-2006, 12:17 AM   #29
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If the LIM gasket is messed up, you'd be leaking coolant or the carb cleaner test would show you the problem. Try it. Between the UIM and LIM, and the LIM and the heads.

Sounds like you need to replace both o-rings in the PCV housing to me. Lube them up with some light grease before install to insure a good seal.
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