97 GT engine squeal

I have an engine squeal coming from my Gt when I let off the gas and coasting to a red light. It only seems to happen after driving for awhile. When I tap the gas it stops, and does not do it under power. I have tried turning off the AC and this does not make a difference. I just replaced the belt and idle tension pulley not to long ago. Any suggestions.

Have you recently replaced the PCV valve, and if so, did you remove the o-ring from the old one and reinstall it on the new one? If not, they will whistle under high vacuum situations.

Any other suggestions, this noise is getting worse, last night I could hear my wife coming down the street. I just changed the PCV valve and I did not see any o ring on the valve its self. I did notice the MAP sensor is a little loose, 2 of the locking tabs are broken (one on each side).

I suggest that you re-read what Rich wrote. You need a rubber o-ring on your PCV valve. You can purchase a new PCV valve kit at your local dealer for around 20.00 bucks. It includes PCV valve, o-rings, and a new MAP/PCV bracket that will help to keep your MAP sensor seated tight. You may have two vacuum leaks, one at your MAP sensor and at you PCV valve.

Thanks, I went today and got the PVC kit for $27 and some change. The MAP sensor holder is a different style but it will fit, it also came with a spring that sits on top of the PVC valve. I will let you know if this works.

Yes, I had the older style also and no spring. The new kit included all of these. Even if this doesn't fix the noise you described, you needed these new parts, o-rings anyway. Good luck and keep us informed.

My water pump made a slight squeal and replacing it fixed it. I have also heard bad bearings in an alternator make a squeal.

I have run into that squeal in the past. Another shop had installed a new upper plenum and did not install the PCV valve. The noise in this case was actually air rushing into the engine through the rear valve cover gasket. I'll admit I scratched my head for a few minutes before I put all the pieces together on that one!!

Just an update, so far so good, no more noise since I installed the new PVC kit from the dealer. Keeping fingers crossed. I will no more tonight since I will travel about 100 miles. Everything else since then has been local driving. Thanks for all the suggestions.

Just got back from my 130 mile road trip and all went well, no noise. Thanks again for all the help.

You are very welcome. Thanks for the feedback as we like happy endings, and it may help someone else reading this thread with the same issue.