Thread: replacing bad ac compressor?

Anyone has a write-up or would be able to tell me how to replace a bad ac compressor? I believe mine is dead since whenever I turn on the ac the compressor doesn’t engage and spin. I also tried to add Freon but the system kept overfilling. How hard of a job am I looking at in swapping the ac compressor out with another one? Also is a used one alright to purchase or should I get a whole new piece? Thanks in advance.

Ive only replaced one AC system and that was on my last Grand Prix. I don't think a used compressor would be an issue, but I would stick a new dryer on there and there's one other part that should be replaced as well that I cannot remember what it is.

I would probably go as far as to flush if not replace the condenser as well. Thats all I can think of at the moment.

new 'dryer'?

Yeah, its the long cylindrical thing underneath where the air box it that hangs off the frame. They are usually not that expensive and are worth the peace of mind in not having debris somewhere in there or in the system that is going to sabotage your hard work.

I know you are going to hate to hear this, but unless you know for sure that the compressor is bad, it probably isn't. My bet would be that you are low on R134A. A bad compressor will usually make some kind of noise. A screeching is a bad clutch. A grinding is a bad piston inside. But a compressor that just doesn't turn on is usually low on freon.

For me, those little cans that you buy at Walmart or wherever don't work. AC systems need to be filled according to weight, not pressure. I tried many of those cans, and I never had good success. On my GTP, the wife's car, and my truck. It would work okay, but not like it should. It wasn't a big deal for me, but the wife wanted AC. So when we were getting her car inspected, I asked the mechanic to take a look at the system. He pressure tested it, said he couldn't find any leak, pulled a vacuum on it to evacuate the system of all the old stuff in there, filled it with new R134A and the correct oil, and it has been working great ever since. I did the same with my truck and my GTP, and they have been working great as well. I spent more money in those cans, gauges, valves, dye tester, glasses, lights, etc than I did just taking it somewhere. I should have let someone with the correct equiptment do it in the first place.

With that said, that is my experience. I know other people who use those cans and they work great. But I never had success with them.

As for changing the AC compressor, since that is what you asked and I want to answer your question. I did mine through the pass side wheel well. I jacked up the car and supported it on jack stands. I removed the pass side wheel and inner plastic fender. From there you can see the AC compressor. You need to remove the SC belt and accessory belt. I used a long extension through the wheel well, and I think 15mm bolts. The extension was long probably 12-15" long. Remove the 3 bolts from the AC compressor. Lay on your back and look up between the engine and subframe. I removed the bolt holding the aluminum flange to the compressor that has the AC lines going to it. Then there is a metal bracket on the back that bolts the compressor to the engine block. Also, make sure to remove the wiring plug from the back. When all this was done, the compressor dropped down and set on the subframe. Then I could slide it out the pass wheel well.

Along with doing the compressor, I also replaced the accumulator (aka drier), the orifice tube, and all o-rings I came in contact with. I got a used compressor from Ed and it has been working great ever since. The other parts, I got at NAPA. As for o-rings. The seals on the back of the compressor they had in stock. The other generic o-rings I need, I just had them give me a couple of each size. At a couple cents a piece, I could afford to have a few extra. Changing the accumulator is important any time you have have the AC system apart. The accumulator has desiccant inside that will remove all the moisture from the air in the AC system. Without changing this, your AC system will not work well at all.

Hope this helps.

Zef, Ive heard that orifice tube (the part I couldnt remember the name to) is hard to get to and replace. Any comment on that or tips on how to go about replacing it.

If the compressor is tested or know to be bad, you need to pull the system down, suck out all of the refrigerant, and then remove the compressor and reinstall the new, using a new gasket/o-ring on the fittings.

You can use a used compressor, I have one on my car from ED cause my compressor was leaking oil out, and was cheaper to replace the compressor than rebuild/reseal mine.

Its always good practice to replace the receiver dryer and the orifice tube when ever your replacing the compressor. The receiver dryer is easy to do, the orifice tube is kinda a PITA to do, but really needs to be done as this is really a filter for the system, and when clogged...can cause many problems.

The orifice tube is located on the drivers side, in line with the receiver dryer, tucked back along the side of the strut tower, under the master cylinder. The replacement part goes INSIDE the fitting, when the line is unscrewed and opened up. You simply pull out the old, and install the new. Easy to replace, just sucks getting to it to do.

Might check the system and make sure its not low on refrigerant, or, check your fuses, and relays and make sure none of those are bad or blown as well before you go though with it all.

~F~

Originally Posted by SyntheticShield

Zef, Ive heard that orifice tube (the part I couldnt remember the name to) is hard to get to and replace. Any comment on that or tips on how to go about replacing it.

Scotty,

It depends on the year. On my 97, the tube is easily accessible below where the PCM sits, kinda just below the master cylinder. I was able to change it pretty easily. But I know on the later years (not sure what year it started), the orifice tube was back on the firewall I think. And yes, this one is hard to change. I never worked on the AC on a later GTP, but I have heard that the orifice tube can be a problem. For this reason, some people don't change them. But on my car, since it was so easily accessible and cheap, I changed it.

sounds like a lot of work. What about if I plan to just purchase a ZZP ac delete? Is the swap as easy as I assume it is? Basically im just thinking just unbolt and remove the ac compressor/clutch and install the ac delete in its place(of course relieve all the refrigant first)?

Originally Posted by fst

sounds like a lot of work. What about if I plan to just purchase a ZZP ac delete? Is the swap as easy as I assume it is? Basically im just thinking just unbolt and remove the ac compressor/clutch and install the ac delete in its place(of course relieve all the refrigant first)?

I have never done an AC delete. But the freon should be reclaimed first. You should not just open the valve and let it go out into the air. A shop should evacuate the system first. But to install, you are half way to replacing the compressor. I would imagine it would take about the same time to install the delete as it would to install a new compressor.

Also, if you install the AC delete, you should, to make it worth it, remove all the lines, the accumulator, and condenser.

thanks guys and derek for your inputs. derek, i do know there's no sound coming from the ac, no grinding or screeching whenever i turn on the a/c. i honestly did try to use the DIY freon recharge, but like u said, they're junk. i prolly do have low freon in the system. i'll plan on taking it to my local mechanic and have them do a pressure check as well as if the ac system is either needs replacement or just needs reoiled and recharged. thanks again guys!!!

Zef, if I may hijack this thread once more, do you have or know where I can find a picture of the orifice tube, I dont think I have ever seen one and would like to know what to look for on my car to see where its at?

Well, it is on topic...so not much of a hack.

But this picture I stole from Auto Parts Fast at RockAuto



Again, this goes inside the AC line and is an inline filter. So if this gets clogged, it can cause your system to act weak. So good idea to change this everything the system is opened up for some reason.

Crap Zef, now Im even more lost, LOL I dont even know where the line would open up to insert anything like that. Oh well, time to open the system up. I need to get it serviced anyway. Well I guess I cant do that without letting all the 134a out, so maybe that isnt a good idea.

I wish I was able to service AC systems on my own, this is a good how to in the making.

Toasty, thank you for your information. I had never thought of the warm rag idea before but that is an excellent idea.