Squeals

My truck squeals real loud when i turn the vents or heat on and my ac doesnt work. Think it has to do with the ac compressor. I believe the clutch is frozen but not sure. Any ideas??

 

I think you’re right

 

AC Compressor is seized.

 

Have you checked to make sure there isn’t a small pig stuck in your vent?

 

Just fixed this problem on my '06 today.

In my case, the clutch had disintegrated. Compressor still good. A little research makes it seem like a common problem at around 160 odd thousand kilometers. 168000 in my case.

The clutch plate consists of three pieces. One outer piece (clutch face which engages pulley), an inner piece which mounts to the compressor shaft, and a rubber middle piece which connects the entire clutch assembly together. The rubber piece had let go and resulted in a horrendous squeal as the inner clutch piece spun within the outer. Bad smell of burning rubber.

I had initially thought the burning smell was the serpentine belt on the the compressor pulley, but it was the clutch rubber.

On the dash, the A/C light was flashing, indicating some sort of fault. No cold air.

I could replicate the squeal (which would last a second or two until the system shut down) by turning on the A/C. After a few times, the clutch was so loose, it stopped squealing and just spun freely. The speed sensor shuts down the system and blinks the light.

I was fortunate enough to come across a used compressor for $50 and used the clutch off of that. I see there are many aftermarket clutches available on Ebay. You can do the swap without removing the compressor (which means no need to mess with refrigerant). Nor do you need to remove the serpentine belt if you're sure it's the clutch. Drop the skid plate and you have enough access. I used a small impact gun to loosen the 8mm clutch bolt. Since the inner clutch piece will spin freely and there is no simple way to hold it still, the impact gun is the easiest way. Otherwise, you'd have to jam a screwdriver or something through the rubber and try to pry the center piece tight, all while working a ratchet, probably whacking it with a hammer. You'll need four hands and only have room for two in that tight space. Buy/rent/borrow a right-angle impact gun if you don't have one.

One thing to note is that there will be a few washers/spacers on the clutch bolt. Don't lose those. You'll need them when reinstalling to ensure a proper gap between clutch and pulley.

There are several good videos on Youtube that illustrate how to replace an electromagnetic A/C clutch and show you what you're up against.

Or, if the clutch is good, you are on the hook for a new compressor, but I'd suspect the clutch first.