3.8 ltr - belt - water pump - noise - Please Help!

I just changed my water pump and belt. (previously this year I also replaced the Alt. and A/C compressor). I finished the job with a new belt. Once I started the car the belt or acc in the area started making a high pitch noise. Tried a spray of WD40 no effect. I took the belt off and started the car, no noise. Turned all the pullies by hand no noise. cleaned every thing with brake cleaner. Next day same noise new belt. And now every once in a while my check engine light comes on for maybe 2-6 seconds. I know the pully for the water pump is smooth. Should this roughed up with emery paper? Any Ideas? Water temp and voltage are good.

What kind of vehicle? How many belts? Is there a belt tensioner? No you never roughen up the pulleys normal tension will spin them correctly. Usually unless the pulley in question has bad bearings you can not make a noise cause you can not turn the pulley fast enough. A check engine light can be caused by any number of things. Usually one of the other parts places will put a code reader on your vehicle and read the code free of charge.

Are you sure the tension on the belt is tight enough? Or not too tight?

Olds 98 1992 - when I listen to the noise I can’t really tell which on it is cooming from. One belt for all.

automatic tensioner. It still is very tight.

On most vehicles the way to test your tensioner is “IN a 12” gap, span between pulleys, it should move 1/4 of an inch when you push it. More movement to loose, less to tight. The other way is to put a torque wrench on the tensioner and pull back it should register about 90lbs.

Another way, is to get a short belt. You install the belt and bypass each individual part, alt, ac, steering, and when there is no whine that is the one that has an issue.

As far as the code, there are to many things that can cause them. You will have to have it read. It may lead you to the bad part that is whining. I recently found my water temp sensor in the front of my motor had broken at the base and fallen off and my service engine soon light was on. I replaced it and the problem went away.

trust me the tensioner is good

Update a little WD40 on belt sound went away for a sesond. On a different note oince the car has sat over night and the car is started thier is no noise for like 10 to 15 seconds.
Sound extremely unpleasent and loud with the hood up.

Back To The Tensioner. “trust me the tensioner is good” It’s Not That I Don’t Trust You, But I Might Not Trust Your Evaluation Method. How Are You Assessing The Tensioner ?

Some tensioners on the GM 3800s have marks (lines) cast into the tensioner’s metal that are there to show when the tensioner is worn out. I don’t know if you’ve got the marks on your’s, but when the tensioner wears it may seem that the belt is quite tight, but it isn’t.

By the way, applying chemicals to a serpentine belt is not a good move, including or especially WD-40.

Goldwing asked about belt tension and didn’t get a real answer. You have to be willing to use advice when you ask for it.

Specifically, how are you assessing the belt tension other than it “feels” really tight ?

CSA