Hi everyone, I have a 2004 G35 sedan 6MT. Recently my belt started chirping. Few minutes before parking the car to work on it I heard on two occasions a horrible squealing noises. As well my battery and parking brake light were on as well even though the alternator was putting out a steady 14.6 volts at idle under load and my battery tester showed my battery checked out fine.

I remove all the crap to get to the belts, replaced them both with Goodyear Mileage Maker belts and hear this terrible squealing noise. Removed the alternator/power steering belt (battery light was still on by the way even after changing the belt for a brand new one, didn't see any loose pulleys from the alternator), changes the A/C idler pulley (new one still has a tiny bit of play like the old one, though do t think it's enough to be causing the problem) and tried another Bandco belt, still this horrible squealing noise with some smoke. Please note this is when the A/C is OFF not on (opposite of most people having a noise when the A/C is on but in my case it's when it's off). When it's on there is no noise. When it's off there is terrible noise (except when you start the car there is no noise, only when you turn the A/C on and then off again there is the noise). Am I doing something wrong? Maybe doing the belt too tight or too loose? Or my AC compressor pulley/clutch is just toast?

​​​​​I have a sixty second video about the problem with timestamps of the noise. In the video only the AC belt is installed and the car is running off the battery. Any help is appreciated, thanks in advance!

https://youtu.be/i_1Pzg1GzBY

Your AC compressor clutch might be shot.

Looks like something is binding up inside your AC compressor pulley, with the belt removed spin the pulley by hand, it should spin freely.

It's probably the clutch, when it's engaged it's magnetically locked to the metal pulley behind it, as soon as you turn it off the magnet releases and the clutch springs forward away from the pulley then it SHOULD be spinning freely. Probably it's bearing is blown out and it's just slightly tilted at an angle and getting bound up anytime it's not engaged.

I bet if you grabbed the clutch and tried to wiggle it around it's probably got play somewhere.

You can clearly see in the video that the clutch isn't disengaging though, the center section should stop spinning when you turn off the AC compressor but it doesn't, it's still spinning in the off position.

Thanks for the in depth response Cleric. That's pretty much the worst case scenario that I feared. I'm currently sick as a dog right now but in a few days when I'm better I'll examine the AC clutch for play. The pulley looked OK though at a casual touch.

I suppose the AC clutch itself is not really serviceable without taking off the compressor and opening it apart? If that is even possible and I might need a whole new compressor?

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The clutch is a separate piece that is pressed into the middle of the AC pulley. They're designed to be separately replaceable and they are serviceable ON THE VEHICLE.

The hardest part is getting a puller into the right spot on the G, typically I use a slide hammer to pull the stuff apart but you can't get one at the proper angle on the G so it typically involves tapping with a plastic dead blow mallet. Not hard, just a little more time consuming.

This video gives you an overview of what the parts are, keep in mind this guy isn't using any of the correct pullers and such so it's a little ghetto but still effective. I would recommend using a feeler gauge when done and making sure the gap on the clutch is like 0.015 - 0.020 though. I'm not sure exactly what Nissan spec is but that's pretty generic for other vehicles.

Thanks for the info, looks doable enough. The new kits look a bit expensive over $100 and I'm not certain they have the same electrical plug and I don't know how to solder nor want to invest in the equipment, I'll just scurry the local pick n pulls and I can "practice" on a junked car first and get the parts cheap. By the puller tool you're referring too, it's the same black plier Craftsmen tool in the video right?

That plier tool he was using is for the circlip / snap ring to remove the pulley. You don't need that to remove just the clutch which is on the very front. The clutch is held on with a single bolt.

I looked around YT and found a video here that shows and describes everything MUCH more clearly for you. Including showing exactly how it works when energized, it's a super simple design, electromagnet pulls the clutch onto the pulley. Those 3 "bars" you see on the front of the clutch are just pieces of spring steel that causes the clutch to pop back out when power is turned off to the electromagnet.

That compressor magnet (he accidentally calls it a stator) is held in with a second circlip which is what most manufacturers use. Nissan uses both circlip and bolts depending on the year. I don't know exactly what's on my 2006 because I've never needed to replace it.

You've been a godsend cleric. So the problem was, there was only one shim/spacer in the clutch hub. The junkyard cars I took the clutches from had two. Unfortunately for whatever reason the junkyard clutches would not go on my compressor (tried two junkyard clutches from one '03 and one '04 I believe), they looked like they had much deeper grooves. Maybe my compressor was aftermarket. Anyway I put in an extra shim on my existing clutch for a total of two, the terrible noise went away but it still didn't sound right. I put in another shim for a total of three and now it sounds like it should, but the gap is still not that big as the electromagnet has no problems engaging the clutch.

I should mention that the battery and parking brake light are completely gone as well. If I went to the mechanic they would try to upsell me an alternator and AC compressor and I'd be $2000 poorer. Thanks to your help cleric I was able to fix it for $150 by myself (and about $80-90 of those parts I bought were unnecessary so was really like $50-60 fix).

Cheers!

Awesome, glad you got it all sorted out.

That's the thing about most auto repairs, they're usually really simple once you understand HOW IT ACTUALLY WORKS.