heater grinding, bearing problem? '97

[purify]

hey guys, just found the forum. I need some help on finding the problem with my car.

when i have the heat on in the car or when the whole ac/heat system is off, i hear this grinding in the engine. it sounds like a bad bearing. but when i turn on the a/c, or turn on the defog or defrost, the sound goes away.

why would it sound bad when the system is off, but not when the a/c is on? any ideas? is it okay to drive around with the a/c on?


thanks in advance!

[GTP Dad]

The problem may actually be with the AC compressor. When the engine runs and the AC is on the clutch engages and causes the compressor to turn. When it is not on the compressor pulley still turns and that may be where the noise is coming from. When the clutch engages it puts torque on the bearing eliminating the noise. It is ok to drive with the AC on all the time but power and mileage will suffer. Eventually you will need to have it repaired anyway. You may be better off to purchase a used AC compressor and get it changed. Don't try to do this yourself as you will need to evacuate the system and pull a vacuum on it before recharge.

[purify]

thank you very much, it's kind of counter intuitive that it sounds broken when it's not working. I just did a quick search and found a compressor on ebay for like $300, it'll probably be twice that to replace with labor though. oh well there are worse things then driving with the a/c on. again, thanks!

[GTP Dad]

I didn't check where you live but check car-part.com for a used one. You can probably find one for less than $100. It won't be new but it should do the job for a lot less money.