My '02 civic is making a super high pitched metallic squeaking sound, but only if the A/C is on, so I'm assuming it's a loose belt? My question is that just a couple of months ago I had a lot of work done on this care - new timing belt, waterpump, power steering belt and alt belt. Is it possible that they loosened the A/C belt while doing all of this other work? Thanks.

Get a simple squirt gun from a 99 cent store, a cheap-o one that sprays a tiny stream... or some other squirt bottle that can spray a stream. fill it with some warm soapy water.

With A/C running and making noise, spray the soapy water solution directly onto the spinning belt (on the inside, which makes contact with the A/C compressor clutch pulley). If the noise stops, you have a belt problem... Inspect and replace the belt if you see any cracks or damage, or simply adjust the belt tension if the belt looks okay.

Since it's a metallic squeaking noise, there's a second possibility. If the noise doesn't stop, you would likely have a failing A/C compressor bearing.

Thanks Green, I really appreciate you taking the time to respond. Some bad news... today the noise was there without the A/C being on. I started the car and it started squealing even though the A/C was off. The blower itself wasn't even on if that matters. Then, since I thought the A/C was the problem, I turned it on to see what would happen and nothing really changed... maybe a slight pitch change in the squealing. I turned the A/C off and then on again and then off again and that last time I turned it off the noise went away.

I'm also going to retract the 'metallic' description I gave the squealing... it really is just that high pitched whining we've all heard in older cars.

Could it be the alternator belt?

just some quick info...the alt and a/c share the same belt. the PS has its own belt. and yes usually that noise is made by a loose belt. new belts do get worn in over time and possibly require adjustment.

If it DOES end up sounding metallic, it is the bearings on the A/C compressor CLUTCH. This is a fairly common failure part. I've replaced it once on my EM2, twice on my EP3 (K series A/C compressor clutches fail a LOT for whatever reason).

Just wondering, how much did you end up spending for parts + labour when you got your compressor clutch replaced on your em2 'ZFreak'?

So I took the car back to the mechanic who had just replaced all of my belts back in May. He said the alternator and power steering belts were both a bit loose. He tightened them up and we were on our way. No more squealing thus far!