Strange noise??

[Raggs]

When I start my 93, when it's hot, I get a high piched hum for about one to two minutes. I thought is was the electric AIR pump, but I disconnected it and still hear it. It's comming from the forward most engine compartment. It's not the cooling fans, I have disabled them also. I wish I could give a better description of the sound, but thats the best I can come up with. It's driving me crazy becouse it resonates so bad that I can't isolate it and it's kind of embarrising!!!! Anyone ever heard something like this? Thanks!

 

[G Winter]

Have you checked the belt tensioner pulley. The bearing in it may be going bad. Power steering pumps at times can make some pretty strange sounds if all is not right with them.Does the pitch change when you turn the wheel? Even the alt. will make noises if bearing or brushes are giving problems. The fact that it does it the first two minutes might point to the alt because it is under heavy load recovering the battery from cranking and drain on it while sitting.Use a dowel or large long screwdriver , put it on the suspected item and put your ear on the other end. You should be able to isolate it.

Glenn

 

[Raggs]

Nothing I do changes the tone. I was looking at this morning and it sounds like it could be coming from the AIR pump vent that sticks up between the pump and the radiator.

 

[G Winter]

Are you talking about the valve system on the air pump?
Could be a problem with that.


Glenn

 

[Raggs]

Yea. The noise is coming from the AIR intake silencer, even with the AIR pump disconnected. I'm wondering if it could be one of the exhaust manifold check valve blowing by. Anyone out there that knows anything about this system?? Thanks

 

[G Winter]

I was kind of thinking the same thing, but I was thinking the pump should be able to overcome that . Unless it isn't pumping.

Glenn