AC Clutch Meltdown (1 Viewer)

[CycloSteve]

No indications prior to the meltdown of the outer nose piece and the electro-magnet. No noise, no shutter of the motor, and AC was previously blowing cold. Simply turned the AC on for the first time this year/season, and within a few minutes the Gauge fuse blows.

Was able to turn the compressor, so it is not frozen.

Disassembly shows the electo-magnet completely melted, wires a big mess.

Any thoughts as to the reason? The compressor assembly is only five years old, with about 40k miles on it. Had a single spacer in place for the air-gap, though could not really verify the gap with all of th melt-down. Clips were all in the correct grooves.

Getting a new assembly, but want to rule out any other issues before I replace it on the truck.

 

[smritte]

In my career, I have replaced literally hundreds of compressors. I don't know if I can count past one hand where the compressor seizing didn't cause that. I have seen compressors seize and break the shaft going into it, giving the illusion the compressors not seized. I've seen "slugging" which is liquid going into the compressor, locking it up but that's almost impossible with our TXV systems. That normally happens when the owner, home charges the system and puts in way too much oil.

Clutch gap issues go two ways, too close and too far.
Too close and you hear it dragging when it disengages. Metal scraping noise.
Too far can cause slipping with high temps. With higher temps, the load on the compressor increases casing the clutch to slip. "IF" this is what happened to you, my concern would be heat damage on the shaft seal. The seal is now weak and will seep out refrigerant over time.

 

[CycloSteve]

The system was serviced/filled by an AC shop after the diesel conversion, and worked fine for the last 5 years.

Is there any way to test the compressor at this point, or just source a new one?

 

[smritte]

Peace of mind, replace it. If the compressor itself is good, the front seal on it is suspect. "if" your lucky, very little heat traveled down the shaft. The main pressure seal is a ceramic seal with a rubber dust seal. Compressor oil keeps the ceramic one in shape. If the oil got hot enough to score the seal, it will leak. Many years ago, most of the seals were replaceable. Not so much anymore.