I know the compressor kicks in and out when using defrost, however this is a weird grinding type noise as the compressor kicks on/off.
The truck is new to me...just bought it used. It's a 2000 Lariat. I'm assuming its a bearing in the compressor, but thought I'd ask if anyone else has run into this sound b4? Or could it be a belt pulley that the bearings are going out on and the load of the compressor kicking on/off is what is making it make that sound? Any suggestions on how to pinpoint it...I can't tell if its coming from the compressor itself or the idler pulley (I think that is what it's called).

 

Anyone want to help with this one?

 

Doe's it make the noise when the compressor is engaged or disengaged? If it does it only engaged, the bearing most likely isn't the problem. If it does it disengaged or it doesn't matter, it may be the bearing. Remove the belt and spin the pulley and see if it seems rough, if it does, the bearing is the problem. Just be aware, it can also be the tensioner pulley or the idler pulley, when you have the belt off spin these also and check them.

 

It only does it when the compressor kicks on, so would that mean it could be the bearing in the compressor itself? Or could it be the fan clutch or anything else like that?

 

I would lean towards the bearing. The fan clutch usually only kicks in when the truck is first started when cold or when it gets hot.

I am referring to the bearing on the clutch for the compressor. That can be replaced without replacing the entire compressor.

 

Will the compressor have to be removed to get at the bearing? Or can it be done in place?

 

You can replace the bearing and pulley assy. with the compressor in place. But, remove the belt and see if the pulley feels rough when spinning it. Check all other pulleys at the same time the same way.

 

I bought a 2000 f-150 XL and the compressor made not really a grinding noise, but more of a whine when it kicked on. i figured that the compressor was going out. A couple of months later i replaced the belt and that noise completely went away. Hope this helps.
-Matt

 

Thanks nascar...I will definitely try that first.