AC Compressor Identification

[MIKE BROGDON]

As always, Thank you in advance for any and all input. I am moving on to tackle the AC in my 94 K1500. Due to a ruptured line from trying to change the high side service valve, I am replacing the AC lines, as well as the accumulator, orifice tube, and condenser. I will be flushing the evaporator as well with the system open. The compressor works fine so I wont be replacing it.

Upon researching replacing the oil in the system, I found a chart on the Mitchell DIY program as shown below. The tag on my compressor is faded and I cannot see the ID information. The chart says Harrison HD6, HR100T, HR110 etc. Does anyone know if the GM OEM compressor from the factory falls into any of these? The only model numbers I found when I checked for new compressors hoping to find an OEM replacement number was LT4.

Also, if this was correct and I placed 3.5 oz in the accumulator, 1 oz in the condenser, and 3 oz in the evaporator, would it be smart to remove the compressor and drain the oil, and refill with new oil to ensure the system accurately had all 8 oz?

Thanks, Mike.

*PICS BELOW*

 

[MIKE BROGDON]

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[Erik the Awful]

Since you're replacing the receiver/drier and condenser and flushing the evaporator, I'd shoot 7.5 oz in there and call it good. I wouldn't bother trying to drain and refill the compressor unless you believe you got dirt and crap in there.

If all you did was break a line, why are you replacing the condenser? It it in rough shape? If not, don't bother. Same for flushing the evaporator. Did you break the line a year ago and drive through sand storms since then? Replacing the accumulator (aka receiver/drier) is required as it has desiccant built into it.

 

[PlayingWithTBI]

The only model numbers I found when I checked for new compressors hoping to find an OEM replacement number was LT4.

That's the standard R4 compressor for our trucks - LT just stands for Light.

If you don't drain and measure the oil in the compressor, you won't know how much to add in order to reach 7.5 - 8oz. I just put 4oz in the compressor and 4oz in the receiver/drier, charge as much Freon I can with the engine shut off, then start it and let it idle for a couple minutes to allow the oil to disperse throughout before charging the rest of the Freon.

 

[MIKE BROGDON]

Erik, the condenser is in very rough shape. And the truck has stayed in the garage since the line tore so I may not flush the evaporator. I'll probably just run with the 7.5.

PlayingwithTBI, copy that. I have never thought of charging with the truck off, but I like that Idea because it will move some of the oil around without running the compressor.

Thanks for the input guys

 

[PlayingWithTBI]

Also a good idea is to check your air gap on the clutch - s/b 0.020" - 0.030". The R4 is a press fit, there's no shims. The nut on the end of the shaft just keeps it from flying off, ha ha. If your gap is too big you'll smoke the clutch. I had a new one from NAPA that was way too big. I bought the kit for adjusting and removing the clutch but some of the compressors are metric and some are SAE, WTF. Anyway, on one I had to tap it in until I got within spec. If it's too tight you need the puller to adjust it out.

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[MIKE BROGDON]

Ok, So by air gap, you are referring to the gap between the back of the clutch and the front of the compressor correct? Did you measure this by using a caliper?

 

[PlayingWithTBI]

Ok, So by air gap, you are referring to the gap between the back of the clutch and the front of the compressor correct? Did you measure this by using a caliper?

That's right, I use feeler gauges. The clutch is a little sloppy, due to the springs, so you need to try to hold it straight and measure at opposite sides, like 9:00 and 3:00.