I apologize if this a repeat but I cant find where my earlier post went, oops! So when I start my car there is a grinding type of noise it does go away when the front defroster is turned on, this also engages the radiator fans, seem normal? The noise sounds like its coming from the water pump, but why would it go away when the defroster is on? Seems to run just fine on the highway
though. Last weekend I did change the thermostat (FUN JOB .....NOT) which the weather since has prevented me from changing the WP.


2000 Monte Carlo 3.4 liter automatic

 

You can't post questions in the How-To section, thats why you couldn't find this. I moved it for you

Turn your AC on, the noise probably went away too. The bearing on the compressor is probably going bad. You can try WD-40 (avoid the belt, just get it sucked into the small gap where the idle bearing is)

 

As a test only:

When it comes to a pully tensioner, or idler pulley bearings etc...

I use a spray bottle with water in it. I put the spray nozzle to stream.
That way you can more accurately direct it at the bearings...
The water then acts like a lubricant, If the squealing,squeaking, chirping stops...Then you found the bearing that needs to be replaced...

This is no way a fix...Just a way to find the problem so you can repair it....