Murray AC Compressor Questions

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jellis56
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Murray AC Compressor Questions

Post by jellis56 »

I am installing a Murray AC Compressor in my 2014 Silverado 1500. I have two questions I could use help with.

1. There is a screw in plug with a sticker on top that covers a tiny hole that goes through the plug. I took it out and verified the hole doesn't go straight thru, it's baffled or something to prevent oil from escaping.

I can't find any info on what this is for and I have not mistaken if for one of the low or high psi lines into the compressor. It almost looks like a breathing hole of some type.

2. What is the best method of adding new PAG 46 oil after dumping out the factory oil? Do I pour it in the low side port and rotate the clutch several times or a better method?

Thanks
GM Tech
Posts: 174
Joined: Fri Apr 22, 2016 7:22 am

Re: Murray AC Compressor Questions

Post by GM Tech »

HPRV otherwise known as High Pressure Relief Valve. It is a safety valve to release refrigerant if indeed the HPCO High Pressure Cut-Off switch does not shut off compressor.


Oil can be put in low side just fine---every compressor shipped to assembly plants has its belly full of all system oil..
Al9
Posts: 253
Joined: Tue Mar 10, 2020 3:26 am
Location: Southern Europe

Re: Murray AC Compressor Questions

Post by Al9 »

Looks like a single sided swashplate variable displacement compressor.

With these ones, usually (some Denso 5SE units are an exception apparently) the compressor housing features a drain hole that allows the entire crankcase to be both drained and refilled with oil. The one on my car has one pointing either downwards (OEM compressor) or upwards (aftermarket compressor) right behind the clutch. There's a normal looking bolt screwed on it. That's where, last August, my new aftermarket comp got filled with oil, belly full of all system oil as GM Tech stated (remainder of the system got flushed of course), made sure to rotate the clutch hub by hand a few times right before letting it run for the first time, and no problems. Purring like a kitten when on.

Compressor should come with installation instructions. Look there.
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