I'm looking for knowlegable opinions on my problem. I have a 2002 Cavalier with 62,000 miles, I beleive it has the GM V5 compressor. For the past 2 years it has a very slow oil seepage at the control valve, at the bottom of the compressor. It forms a drip every several weeks. The A/C system is still working great, but someday it is going to run out of oil!! At the auto store they have a 2oz oil charge (no refrigerant). I am thinking about adding 1 or 2 ounces of pag 100 or 150 to keep me going for another season. I think the refrigerant levals are ok, because it blows cold and no cycling. I am open for anyones thoughts. Thanks :confused::confused:

How are you going to add the oil without opening up the system? You would need an oil injector tool. You don't really know how much oil has leaked out, although you might be able to guess and an ounce sounds about right. It's hard to imagine only oil came out and no refrigerant. I would just put new o-rings on the control valve and recharge the refrigerant. The control valve should be removable without having to take the compressor off.

It's hard to imagine only oil came out and no refrigerant.

:iagree: Refrigerant leaks out much faster than oil (smaller molecules). I'd think you probably have an engine oil leak over the compressor that is dripping off the compressor. If it was dripping once a week for 2 years, you'd be out of refrigerant and oil, (without looking up the actual specification) generally an A/C system would hold a total of 8 oz of oil. Also, there would be many more drops of oil that fell off while driving that you never saw. You know those black marks in the center of the lane after dips where the suspension is compressed for the first time after it? Lots bigger than the oil puddles in parking lots!

Now to sound like a newbie, control valve? I remember no such part!? Maybe I called in sick on that day...

:iagree: Refrigerant leaks out much faster than oil (smaller molecules). I'd think you probably have an engine oil leak over the compressor that is dripping off the compressor. If it was dripping once a week for 2 years, you'd be out of refrigerant and oil, (without looking up the actual specification) generally an A/C system would hold a total of 8 oz of oil. Also, there would be many more drops of oil that fell off while driving that you never saw.

Yeah i agree. I don't think you could lose oil and not lose refrigerant. I'm assuming he just has a very slow leak and hasn't lost enough refrigerant yet, or oil is leaking from the engine on to the compressor like you said. He should do a refrigerant leak test.

Now to sound like a newbie, control valve? I remember no such part!? Maybe I called in sick on that day...

the GM variable compressors have a control valve that controls the A/C pressure by varying the compressor stroke. It's an ingenious design by GM. Mostly no one messes with it, but I guess sometimes the o-rings can leak. They use to come with different low side pressure ratings (and how cold they let the evaporator get) and were color coded. Maybe they still are available like that.

I would like to thank everyone for their constructive replys, it's like a think tank, I like that. I'm a newly retired industrial machine mechanic. My A/C skills are not professional, more of a home wanna be. I'm trying to temporaraly avoid another project, too many unfinished ones now. I'm pretty anal when it comes to observing and diagnosing a problem. My oil seepage is definatly an O-Ring at the colored coded control valve, which is located at the very bottom of the compressor (like a sump area). My theory is some uncirculated oil is laying at the bottom of the compressor and is the first to be pushed out, then followed by refrigerant at a faster pace. At the auto store they have a 2oz presurized can of pag oil that I believe I can add at the low side. Has anyone ever used these 2oz cans? What do you think? Also I hope some day I can contribute to someone elses opportunities. Thank you, Richard:rolleyes:

My oil seepage is definatly an O-Ring at the colored coded control valve, which is located at the very bottom of the compressor (like a sump area). My theory is some uncirculated oil is laying at the bottom of the compressor and is the first to be pushed out, then followed by refrigerant at a faster pace.

I think your assumption could be fairly accurate but my guess would be that your leakage is happening while the compressor is running and the pressure is higher and the compressor is and oil is hotter. and the oil is circulating and emulsing with the refrigerant. Where ever oil is leaking out refrigerant is too.

It doesn't sound like you've lost much oil or refrigerant, but the leak will probably get worse. The real fix is to replace the o-rings on the contol valve.


I was just curious what color is your control valve?


At the auto store they have a 2oz presurized can of pag oil that I believe I can add at the low side. Has anyone ever used these 2oz cans? What do you think? Also I hope some day I can contribute to someone elses opportunities. Thank you, Richard:rolleyes:

I have used those before and I don't think they work that good. A lot of the oil remains and some of the pressurized refrigerant remains in the can, plus it coats your charge hoses. The funny thing is the short cheapo charging gauges work better to use with these oil cans than a good manifold gauge set which long lines will get coated with the oil.

I personally think trying to add oil with the can will probably replace whatever you lost since it doesn't sound like you've lost much, but it's a band-aide and mostly a waste of time. I would fix it like I suggested earlier. Replace the o-rings, open a line somewhere convienant and put an ounce or 2 of oil in, pull a vacuum and recharge.

I know those V-5 compressors inside and out- almost always it is the rear head to cylinder o-ring leaking- are you sure the leak is at the control valve? I rarely if ever see those- but there is a first time for everything. Corrosion crawls in up under the o-rings and cause the leaks- due to the fact the compressors are not painted.

I typically re-seal those compressors. new shaft seal, and new body o-rings, to solve the problem- but I do have to clean the sealing surfaces first.

As far as replenishing the oil, from all my testing, you can actually run on half the total system amount (9 ounces) and still cause no compressor harm, all the internal crankcase parts that need lubed are running under oil and in a splash zone- this crankcase has typically 3- 3 1/2 ounces in it. I have oil injector that attaches to the low side and you push it in, like a syringe, but the easiest for you would be the cans with oil in it- just turn them upsidedown when filling, slowly- on the low side- in front of accumulator will cause no slugging.

Gentlemen, I would like to thank all of you for your input. I've learned something from everyone.
I have cleaned the case several times and the seepage seems to always start at the control valve.
I will only add oil, with the short cheapo hose, if I don't do the o ring job shortly. O Ring Kit includes new dust cover-A/C delco #15-31822, GM #88918512.
The color coating seems to be gone now (cleaning?). As I remember it was a dark red or maroon, the black dust cover has been partially missing for a few years. That corrosoin information is good, I've seen that on other things before. Thanks, Richard :)


Note: I hope our American car manufacturers work out their problems. I'm old now, but I've had a love afair with all our American cars since I was a boy.

2002 Chevy Cavalier/Wife
1985 Chevy S10/Me
1964 Chevy Corvette/Garage:licka:

Sounds good. Here's the color code chart. I'm not sure what "tay" and the alphabet character in its column represent. As you can see the green is the coldest and red is next to the highest. Actually "X" might be the coldest but I'm not sure if it is plain (how would you know if the color just came off) or some unspecified color, or if it's even available. Under 30 could freeze the evaporator.

When I replaced my compressor with a new GM on my malibu, I think the new compressor had the the highest orange or maybe red, so I figured my old control valve was cooler, and I switched it out. My original control valve didn't seem to have a color so I don't know if it wore off or maybe it's an "X". All I know is my A/c is very cold. I think later models run at a higher temperature than early models for efficiencyand are usually red or green. I like my A/c to be cold like the good ole days with R12 and 3 lbs of refrigerant :lol2:.



http://www.autoacforum.com/forumimages/color-chart.jpg

So if I want to switch the control valve on my car to the coldest one, I just call the auto parts store and ask for an "A/C compressor control valve", or is it a dealer only thing? I've ordered parts from our suppliers web site many times, and I don't remember ever seeing one listed. I need to replace those O-rings where the lines bolt on, I figure as long as I have the system sucked down anyway I may as well get it even colder. It's cold now (or was last year till a lot leaked out), but it's not COLD :)

So if I want to switch the control valve on my car to the coldest one, I just call the auto parts store and ask for an "A/C compressor control valve", or is it a dealer only thing? I've ordered parts from our suppliers web site many times, and I don't remember ever seeing one listed. I need to replace those O-rings where the lines bolt on, I figure as long as I have the system sucked down anyway I may as well get it even colder. It's cold now (or was last year till a lot leaked out), but it's not COLD :)

Can you determine what color dot is on your CV? I've heard most of them are brown but seems like most of the replacement compressor come with an orange one that I've seen. I'm not sure where you could find a CV with the lowest rating. Most of the control valves and compressors for that matter are made in China and Korea and they list the different colors but want you to buy in bulk. Most parts stores seem to list just one control valve for each application and I don't know what rating it is.

I'm just guessing the late 90's ones had colder ones so maybe you could pull one out of the jumkyard that has a lower rating. I don't think they go bad much.

I'll have to check the color on Saturday, I'm going in to work to do a few things, may as well use a hoist :) If it's that hard to find a specific color, I'll probably just leave it, it's plenty cold - I couldn't even leave the blower on high for more than the first 10 minutes last year on recirculation unless I was in FULL sunlight. I just figured if I could get it colder I would.

Well if you stil have your original control valve it's probably plenty cold. I'm think it's the replacement new compressors even oem ones that are maybe not as cold. As long as your low side pressure is somewhere around 25-35 psi, it should be cooling good.

control valves are rated by the system they are on- J-car control valves are different from N-L-S-W cars- so if you want the same color- just get one from the same model compressor. Your only risk by going to a lower setting- is evaporator freeze-up. The control valves are different because the length of the suction hose from evap to a/d to compressor- and the setting differences account for the pressure drops in that distance of plumbing..I can look up what exactly color yours takes based on model number or compressor.

control valves are rated by the system they are on- J-car control valves are different from N-L-S-W cars- so if you want the same color- just get one from the same model compressor. Your only risk by going to a lower setting- is evaporator freeze-up. The control valves are different because the length of the suction hose from evap to a/d to compressor- and the setting differences account for the pressure drops in that distance of plumbing..I can look up what exactly color yours takes based on model number or compressor.

Good points Brcidd. I'm not personally worried about the potential for evaporator freeze up. I still suspect that replacement compressors are consolidating parts by offering a higher setting valve for most application and maybe later models don't run as cold. Can you look up the color for a 97 Malibu?

I can look up what exactly color yours takes based on model number or compressor.

I'd sure appreciate that, '04 Cavalier. I didn't think about the evap. freezing, don't really want that... kindda defeats the purpose of making it colder :). Maybe just look up what car is one rating colder? Mine was almost painfully cold last year on full-blast after a while, but it did take a few minutes to get comfortable after sitting in the sun, really just looking to speed that part up a bit. Thanks!

A '97 Chevrolet Malibu used OEM compressor model 1135437- has a mechanical destroker- (compressor destrokes at high engine rpm) and a brown control valve- with a dust cap over it..

A 2002 Cavalier/Sunfire used a OEM compressor model number 1135438- also with mechanical destroker and a brown control valve and control valve cover

A '97 Chevrolet Malibu used OEM compressor model 1135437- has a mechanical destroker- (compressor destrokes at high engine rpm) and a brown control valve- with a dust cap over it..

A 2002 Cavalier/Sunfire used a OEM compressor model number 1135438- also with mechanical destroker and a brown control valve and control valve cover

Hey thanks. Well this confirms what I've heard that most GM compressor have a brown control valve The replacement new Delphi one had an orange control valve . I'm glad I switched out the control valves. Where do you find info like that?

I just look over my shoulder....or on my laptop, or on my desktop

I looked over my shoulder and saw nothing but a wall and part of a door, you must have a special shoulder :rofl:

I appreciate you looking that up, but '02 has a different engine than '04, and I assume a different compressor. Could I get you to look up the '04, and if it's not too much work, check what vehicle would have a yellow or purple valve? Or a GM part number for just the valve? Thanks again.

The 2.2L used a 1135438 compressor- which is the brown valve-- my chart stops at 2002 MY-- But if your compressor is a 5438 on the edge of the label- then it is/was a brown valve..

I'll have to wait til I go back to work on Monday to answer the yellow/purple valve question-- My "wall" is in my cubicle.....at work

Thanks!