Nissan Repair: 2003 Nissan Frontier A/C related Squeak, nissan frontier, center bolt

Question
I have a 2003 Nissan Frontier with a 4cyl engine that has developed a
squeak that seems to be related to the A/C. It only happens while driving. I
can't get it to replicate at idle so I can find it, although the truck is noisier
at idle than it used to be. It started as a short chirp, but has progressed to a
longer squeal that nearly sounds like a loose belt. I can feel a slight
hesitation in acceleration when it happens. If I turn off the A/C, it stops. The
belts all look good, and tension seems good. I'm thinking either idler pulley
going bad or maybe the A/C clutch? Or maybe you know of something
else... Thanks for your help.

Answer
Hi Chad -

Your diagnosis is right on.

First of all, get some WD40 and lightly spray the belt while the engine is running (do not get any on the A/C clutch). Take a test drive and see if the squeal is still there. If not, then you will probably have to tighten or replace the belt.

If the squeal is still there, then do the same (WD40), this time on the A/C clutch. If the sound goes away, then it is probably the clutch that is causing the noise. However, it could be because of excessive drag from the compressor (especially since you say it has a loss of power while the A/C is on).

To check the idler, if you have a mechanic's stethoscope, touch the center bolt while the engine is running. If you hear a vibrating or metal to metal sound, it is the pulley. You can also perform this test with a long screwdriver.

Hope this helps -
aloha
calvin