: Doing an A/C overhaul in a Chevy.



My_favorite_Brougham
04-11-11, 12:19 AM
So I think the most educated GM car people are here, and maybe yall can answer a few questions about my dad's 2004 Chevy Classic A/C. It's basically the old body style Malibu with the smaller 2.2L motor.

But anyway, this weekend I am replacing the compressor, accumulator, and orfice tube on his car. I'm going to flush all the components and pull a hard vacuum before recharging the system. Gotta get ready for this Texas heat!

So far I have a brand new Delphi compressor and accumulator. (Thank you Amazon!) I also have all the gauges and plenty of r-134a. But I don't yet have an orfice tube or PAG oil, because I don't know which to get.

There's so many different PAG oils: 46, 100, 150. And there's many orfice tubes ranging from $1.99 to $80.

So which do I get? the cheap orfice tube, or one for 30 bucks? And how do I know how much oil to put in the system? I know the standard is about 7-8 ounces, with half in the compressor and half in the accumulator.

And do yall think I ought to replace my high pressure switch, and the clutch cycling switch? I'd hate to get everything recharged just to have one component ruin it all.

Any recommendations would be gladly appreciated. Thanks friends!

-Greg

Ranger
04-11-11, 12:39 AM
Why are you replacing all those parts? Compressor failure? If so, remember you can't flush the condenser very well. It should be replaced or you may wind up replacing the compressor again if there is any debris in the condenser and it makes it's way to the compressor.

I think the size of the orifice tube is more important than the brand.

I am just guessing that all GM cars use PAG150, but verify it before taking my word on that.

Oil is added to each component per the FSM. I could give you the amounts for each component from my FSM, but I am not sure that would apply to you make and model. I suspect that may not be a generic number.

My_favorite_Brougham
04-11-11, 12:56 AM
The compressor has a blown internal seal; I suspect as a result of being overcharged. It turns, but does not compress the refrigerant. As for the accumulator and orfice tube, those are the standard replacements for when you open a system. I'm hopeful the condenser won't need replacing; we'll see what kind of debris I find (if any).

The rest are just optional, and as far as I can tell they still work (high pressure switch and clutch cycling switch). I was just curious if I should replace them preventatively since it would be convenient.

mhamilton
04-11-11, 02:02 PM
So which do I get? the cheap orfice tube, or one for 30 bucks? And how do I know how much oil to put in the system? I know the standard is about 7-8 ounces, with half in the compressor and half in the accumulator.

And do yall think I ought to replace my high pressure switch, and the clutch cycling switch? I'd hate to get everything recharged just to have one component ruin it all.

Don't waste money on the VOV (Variable Orifice Valve) they're a gimmick. Get the standard $2 orifice tube for your car, don't change the size (plastic color indicates size).

You'd have to check the FSM. GM did use PAG150, but some more recent switched to a slightly lighter viscosity.

No need to replace the cycling switches. Even if they do go bad down the road, they have schrader valves and you can replace them without discharging the system.

If you find any debris, you have to replace the condenser. You can't flush a parallel flow condenser, it will trap debris and ruin the new system.

Actually, the best source for ac information (and parts) is www.ackits.com. They have a great forum and guys there that work on ac all day all year long. They could tell you oil viscosity for sure.

My_favorite_Brougham
04-11-11, 02:50 PM
Thanks Mr. Hamilton!

I went to Napa today and they told me PAG 46 is the one. As for the condenser, I found out it's serpentine flow on these cars. So I can flush it, thankfully.

Greg