Hey guys, just want to start off by saying how grateful I am for this resource and thank every contributor for their time and effort.

I tried to do a little research on the forum and internet before I decided to post a thread, if my questions do sound redundant, pls. let me know. I apologize in advance.

so I basically have two problems;

PROBLEM #1
the title of this thread refers to this problem. Before I get started, i just wanted to clear up some terminology for my sake and the sake of effectively describing the problem. The air conditioner has a FAN that just blows air and it is only when you turn on the COMPRESSOR does the a/c start cooling the air that the FAN then blows out. SO, while my car is on and idling, as soon as i turn the compressor on, i hear this noise coming from the engine block. As soon as i turn the compressor off (at this point the a/c fan inside my car is still blowing) the noise stops. Is there a problem in the belt? If so, is this a serpentine belt? How can it adversely affect my car in the long run if i don't fix it? does it affect the way my car would run? How would I get it fixed? approximate costs?


PROBLEM #2
while my car is idling (usually around 666 rpm), sometimes the rpm will fall to 333 and as it does the car will shudder a bit as if it were about to stall. I do drive a stick ans this happens while the car is in neutral. What could cause this? Is this problem a cause for concern?

THANK YOU FOR YOUR TIME.

 

your a/c noise could be the belt slipping on the pulley when the ac clutch engages, the clutch slipping on the compressor, or the internal parts of the compressor itself, you could try adjusting the belt tension to correct the problem. If it is a squealing noise, you probably have a belt problem. If your belt has not been replaced in a while, inspect it for wear and replace as necessary. A better description of the noise would be helpful.

 

it is a very high pitched repetitive sound (moderate volume, not that loud). How imp. is it to change? will it only affect my /c? How can i tell if it only needs to be adjusted or changed altogether?

 

it's most likely the belt if it's high-pitched and repetitive. if it's slipping, it's getting hot and can break down the belt and get worse or break. Slippage will also decrease the effectiveness of your a/c and heat up the pulley, which heats the bearing. look at the belt to see if it is glossy or has missing ribs, or is cracking or frayed. you can tighten it by loosening the bolts on the alternator and tightening the adjusting bolt on the alternator, then retightening the alternator. only tighten it a little if it is loose. overtightening will wear out bearings. Consult a repair manual for help and for the belt deflection setting. Replace the belt if it has any signs of damage. very small cracks transverse to the ribs are okay and normal if the ribs run on the outside of a pulley. I doubt yours do.