Hi.I guess I'm gonna take my X in and get this checked,but while I'm waiting....let me run this by you guys....

2004 XTERRA , 4 cyl / 5 speed

I have this squeal. At first,it seemed to happen at any time,regardless of a/c use,but now,it seems to mostly happen DURING a/c use.

I realize that this means the pulley or possibly the compressor is bad.However,many times,it occurs with no a/c use....like when the road is wet,foogy days or for no conceivable reason.

Is this a Nissan thing? And is it most likely a pulley and/or a/c compressor? When it first happened,a mechanic told us that all Nissans eventually do this and just "soap it" .

What do you think,guys? Y'all seen it all,I guess.

The A/C compressor is engaged when you operate the system in defog/defrost mode even though the light does not come on on the A/C button. It does not stop even if you turn the knob the other direction until you shut the engine off.

Check the belt. I'm not buying a mechanic telling you all nissans do that, my mother's altima never made a noise for the 145000 miles she had it, and a friend's pathfinder was quiet for almost 200000 miles before he hit a tree. If the belt is good and the compressor is bad, start asking why it failed. I've blown 2 compressors. One was due to an overcharge, the other failed due to a bad shaft seal that allowed it to suck water in when it got hot.

Thanks,thanks....that all makes sense,so I guess it is off to get someone to look at it.The belt looks great,new even.....That would've been the cheapest diagnosis.Oh well!

How's the belt deflection? What I mean by that is find the longest span of belt between the two pulleys, and push and pull the belt. It shouldn't be more than 1/2" either direction from mid point. Just something else to consider. New belts do stretch and should be checked after about a week to make sure the deflection is still within spec. If not, it could squeel.

Sounds like the belt needs to be tightened.