My car makes a squealing noise after its driven for a little while ,but if you pull the oil fill cap off alot of air sucks into the crankcase and the noise stops. I've tried replacing the pcv valve with a new factory gm valve but it didn't help. the car is a 96 olds 98 regency with a 3800 series II. I've taken it to a few garages but they always give me the wrong diagnosis and its getting expensive so please help..(i've replaced the water pump power steering pump and the tensioner pulley)

Is this the sound of like an air leak thru some split? The PCV is removing vapor in the crankcase - has grommet, hose etc., and burns that vapor. The vapor removed causes and is supposed to create a slight vacuum in the crankcase area - all areas involved and allow filtered air to replace what was removed thru another hose or some method. Seems like that it quits when oil cap is removed this is a small leak and you might find it by spraying some WD-40 on areas that should be sealed tight and see if you find a spot that changes the noise - with all intact and making the noise I bet it will show itself.

Careful spraying anything flammable at or on a running or hot engine - especially exhaust parts. Use judgement or perhaps you could just use some spray water,

T
Tom Greenleaf - MetroWest Boston - USA
_________________________________________

http://www.autoacsystems.com/tomgreenleaf/

the sound is similar to that of a bad belt and I've actually tried the wd-40 tip that you gave me but i only sprayed it around the valve covers so ill give that a try in a few other areas thanks for your help.

If this is the type of PCV valve system that is hidden underneath the MAP sensor, inside the intake manifold; it’s suppose to have an o-ring seal around the valves main body, this is to seal the valve too the crankcase.
I’ve seen a number of times that someone has replaced the PCV valve and forgot to change over the o-ring. With this o-ring missing; full manifold vacuum is applied to the crankcase and will make the sound that you’ve explained.

Dan

Canadian "EH"


(This post was edited by DanD on May 3, 2008, 12:42 PM)

is the o ring supposed to be around the valve itself because there is an o ring but its around the housing that seals over the top of the valve. Also the map sensor is above it as you said, can the map sensor be the problem? As i was removing it i noticed that the top and bottom half of the sensor were separated. I'm not sure if this is normal or not but I'm not getting any check engine lights so at least the electrical end of the sensor is still operational. and thanks agian for all the help i really do appreciate it.

The seal I’m talking about should be around the fatter part of the valve. The smaller one around the top is more or less a bumper to help hold the valve in place.

Dan.

Canadian "EH"

I went and got a pcv grommet and installed it but it didn't take care of the problem and i"ve been spraying every possible spot i could find that might be leaking to cause the noise and have had 0 results so im going to attach a video with sound so that you can hear the noise for your selves. thank you again for all of the advice. .......Jeremy I had to post the video on Google because the posts wont accept its size. http://video.google.com/videoplay
it could take up to 24 hrs before the video can be viewed




(This post was edited by Jboulton on May 9, 2008, 11:30 AM)

I don’t mean to harp about this PCV thing I just want to make sure that it isn’t the problem.

Here’s a link to a site that I found showing the valve replacement procedure and the black o-ring that i'm talking about.

http://macgp.clubgp.com/...gine/pcv/gt/pcv.html

Dan.

Canadian "EH"


(This post was edited by DanD on May 9, 2008, 2:41 PM)