AC Clutch / Squealing Problem

[plundccre]

My 2001 QX4 makes a very loud squealing sound for about 15 - 30 seconds every time I start it up then it stops and is quiet for the rest of the drive. I initially thought it may be a loose belt but it appears that maybe the AC Compressor clutch bearings are going out. I notices what looks like some rust dust in the area. Does this seem like a reasonable assessment? Can the AC clutch be replaced without having to replace the entire compressor? Any othe thoughts on what it may be?

[Towncivilian]

What brand belt are you using?

[plundccre]

I'll have to check. They have been on for awhile. Not new ones. We now have 105,000 miles on the vehicle.

[Towncivilian]

Perhaps it's time to change the belts then. Inspect for wear and replace with an OEM belt (should be around $18) if too worn or cracked. Otherwise, I'm not sure what you should try, perhaps verify belt tension. I've never replaced my belts nor know too much about them.

[Densetsu]

First thing's first: did you try tightening the belt?

Can you have someone start it up cold, then verify where the squealing sound is coming from? A mechanic's stethoscope helps here.

[yeldogt]

Make sure the AC is "off" and then see if it makes any difference - Normally when the compressor clutch starts to go -- they burn out quickly and you will smell it. The light rust on the face of the clutch is normal after 10 years +


I bet it is the power steering belt -- unless the belt is obviously loose the best thing to do is replace them. The belts last a long time but once they begin to slip thats the end of them -- you don't want to over tighten. I would order the OE belts from one of the online Nissan dealers - not very expensive and you know you are getting the correct one. Make sure the various pulleys are clean before you put the new one on

[ARKQX33V6]

plundccre the next time you start up your cold vehicle bring along a spray bottle filled with water only, no soap, no nothing just water.

Start the engine but before you so open the hood.

With the hood open and a cold start go out and stand in front of the vehicle and spray that bottle of water onto the noisy fan belt, do just that belt. The water will act like a lubricant between the belt and sheave, if it quiets down then replace that belt. When doing that the sheave or pulley will need a good cleaning. Brake cleaner is a useful tool.

A/C pumps have their oil in part within the freon. While the belts are off check the rotational effects of the pump. Although direction is fixed feel for hardness, roughness and play. A piston pump is somewhat hard to spin and these pumps are about 3 tons of cooling and about 3-7 HP. If a bearing is failing you should feel it, but I doubt that it has a bearing going. A seized pump or close to being seized puts a lot of torque pressure on the driver and as such the drive belt should be mangled.

So when testing for the squeal check the belts, the bearing of the driver and driven components.

When using water as a lubricant the good thing is it will dry by evaporation and leave no residual, but be careful around the electronics, spark and electrics. The fan will pick up the sprayed water and bathe you.