i got 3-4 oz of ac oil in the system, I have about 20 oz of freon in the system. AC blows cold but for some reason everytime the compressor turns on it sounds so nasty..... like a humming whining noise what could it be?

 

Spray some silicone spray onto the belt where it hits the ac pulley, if the noise goes way either your belt is bad or the tensioner is failing. If the noise doesn't go away it's possible your ac clutch bearing is freezing up or the internal bearing is freezing up. You need to fix it before the compressor siezes up because that would be disastrous for the system. You can get a belt for a dx model as a temp fix if that's the case until you can get it fixed. It will bypass the ac.

It's possible the sound could be the tensioner bearing siezing up or the alternator bearing seizing up or even the ps pump seizing up.

 

Ditto the above^^^ it may be the front compressor bearing, the belt or the idler wheel bearing.

Have you tried to isolate where the noise is coming from?What is the MM&Y of the car? 94

 

Well first I put a new belt and tensioner thinking that's all I needed for ac to operate. I was wrong, afterwards I found out I was completely out of freon and I needed a new condenser fan. But the belt was cycling on the pulleys and the pulley tensioner with no problems. I just replaced the condenser fan and it spins freely with no problem. When the ac button is off the ac belt still spins.. the moment I turn the ac button on the compressor makes an ugly whining noise... it's a remanufactured compressor replacing the original a few years back. Since it seems to only make noise when the ac clutch engages is it possible that's the culprit? Or could it still be compressor internals?

 

Ya it comes from the compressor when the ac clutch engages. It's a 2000 honda civic si. I knew it made noise before because I manually powered it to test it before I put freon just to make sure it was operational. I thought the noise would go away once ac oil and freon was put in...now that 60 bucks of ac fluids are in there I'd hate to let it get drained and waisted...

 

The problem is the compressor front bearing.
The oil and refrigerant charge for your car is 5oz oil and 23oz R134a refrigerant, use Ester oil as it is compatible with all R134a and R12 A/C systems. 94