Question about AC compressor drag

[SalahHH83]

So I didn't know where else to put this question. I figure it's pretty much an engine maintenance question.... I have an 88 GMT400 and the AC works on it, but cutting it on causes a HUGE amount of drag. The compressor also makes a good bit of noise when cut on (almost like grinding). It works fine, but the amount of drag and the noise makes me think there is something wrong with the compressor (Duh!i Right?)

Well the truck is new to me, so I don't know its history. My question is this common with GMT400s? Is it something as simple as the AC system not having enough oil in it? Is it compressor damage? Also, are there any other compressors - maybe from a newer truck with a more efficient design - that can be swapped in?

Thanks in advance!

 

[IOWNJUNK]

Is that system R134? I don't remember when it changed. Sounds like the clutch on the compressor is bad.

 

[IOWNJUNK]

Found the compressor with clutch at autozone for under $200, if you have a/c that works and holds a charge then this should be all you'll need. (plus new freon) http://m.autozone.com/autozone-mobi...U-2WD/A-C-Compressor/_/N-ihs7nZ91sgi?id=70575

 

[SalahHH83]

It's an R12 system. I believe they changed in 93 to R134a. I guess my question is how much drag is normal on these GMT400s? The only other truck of this era I had was an 88 Suburban 2500 with a 454. IF there was any drag from the compressor, you'd never know it with the 454.

My truck currently has a 305 (swapping in a Vortec 350) and the drag is VERY noticeable. The sound its making is also painfully obvious. The AC still works, but it does take a while to get cold (makes me suspect it might have been charged with R134a at some point). I'm curious what other people are doing with the older R12 systems.

 

[someotherguy]

I would be more likely to figure the compressor is grinding itself to death and you'll find the system is contaminated with millions of tiny little pieces of it. If you swap on a new compressor without flushing the system out thoroughly, along with replacing the expansion valve and accumulator, you'll be eating that compressor as they won't warranty it when it dies shortly after; they'll be able to see you ran it on a contaminated system.

Richard

 

[great white]

I would be more likely to figure the compressor is grinding itself to death and you'll find the system is contaminated with millions of tiny little pieces of it. If you swap on a new compressor without flushing the system out thoroughly, along with replacing the expansion valve and accumulator, you'll be eating that compressor as they won't warranty it when it dies shortly after; they'll be able to see you ran it on a contaminated system.

Richard

What he said.

 

[SalahHH83]

I would be more likely to figure the compressor is grinding itself to death and you'll find the system is contaminated with millions of tiny little pieces of it. If you swap on a new compressor without flushing the system out thoroughly, along with replacing the expansion valve and accumulator, you'll be eating that compressor as they won't warranty it when it dies shortly after; they'll be able to see you ran it on a contaminated system.

Richard

My suspicion was that the compressor is failing and that's where all that drag is coming from. It makes complete sense bc the amount of drag and noise I was experiencing could not be normal. I don't ever run the AC bc of that. I'll probably just continue to run the vent and windows open, but summers in South Carolina can get downright sweltering so I might be forced into action! haha

 

[t93k2500]

My converted r12 system has very noticeable drag with the 350 and a new GM compressor. Also cycles quite often though not low on refrigerant, and never seemed to cool as well as good ole r12.