A/C not working in Geo Prizm

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Hi, I have a 1993 Geo Prizm and I'm trying to get the A/C working in it. Originally, a friend of mine gave me this car because he thought the transmission was bad and just wanted to get rid of it. Long story short, the car had several minor problems but the tranny was ok. The worst problem is that the A/C does not work. I has been converted to R-134a though.

When I openned the hood, I noticed that there was no belt going from the crank to the compressor. The pulley on the compressor rotated freely by hand, so I figured the compressor wasn't frozen. Unfortunately, I don't think this is the case. Once I put a new belt on, turned the car & A/C on, the car made a high-pitched screaming sound and the engine died.

So I have a couple of questions. I think the compressor is frozen. I'm fairly certain the clutch works, because as long as the A/C button is not pressed, everything works fine. Once the button presses, I assume that's when the clutch engages and all heck breaks loose.

I called up Speedee (oil/lube/etc shop) and they want 60 dollars to check the system, and they probably aren't going to tell me much more than I already know. But they said that I might need a new receiver/dryer.

So my questions are:
Are there any other possible causes for the behavior described in the paragraphs above the one about Speedee? (clogged hoses, etc?)
Under what conditions would I also need a new receiver/dryer if I replace my compressor?
Anything else I should be cautious of?

posted by  kanato

high screaching noise? sounds like a loose belt, or just too tight, could go either way.

i would just go ahead and take the compressor out and have a look at it instead of just guessing.

posted by  Inygknok

I put a new belt on myself, and the tension seems like it's about right, according to the rule of thumb that the Haynes manual suggests. It spins just fine when the clutch is not engaged.

posted by  kanato

So if I were to take the compressor out and look at it, what would I be looking for?

posted by  kanato

I'll save you some time: From what you described, your compressor is locked. If you put a belt on it, the free wheeling pulley is fine till you press the button inside, when you press the button the compressor clutch is energized and then it squeels. Look at the compressor, you will see if the compressor shaft is now spinning or if the belt is slipping. The compressor plate locks to the free wheeling pulley once the electromagnetic clutch is powered. If she's locked, the belt is slipping and making a horrible noise. If the compressor IS spinning you having something horribly wrong inside it. You can also grab the compressor plate and spin it with your hand. It will NOT be loose but it WILL rotate if she's not locked up. Do this with the engine off OF COURSE! It doesn't get any easier than looking at the compressor to determine if it is spinning or not and/or locked or not.

In either case, I can almost feel comfortable telling you that to start with, evac. the system and pull the compressor. Have it checked because the symptomology you just described SCREAMS a bad compressor. You'll probably have to replace the compressor and then go from there. If you don't know what you are doing, I'd HIGHLY recommend getting a certified a/c shop to do the work. You'll need to evac the r134a and then once the system is repaired, you'll have to pull a vacuum on it for at least an hour or so and hit it with a charge. Good Luck.

posted by  cmeseadoin

Ok, this is basically what I figured. My plan is to find some certified mechanic that can do the vacuum work, but buy/replace the compressor myself. But I'm being told a variety of conflicting information from different places, and I'm wondering if you can maybe claify.

On one hand, I'm told I can probably get away with just replacing the compressor and flushing the system. I had one mechanic tell me that I would probably have to replace the compressor and receiver/dryer. A third has told me that I need a new compressor, drier, orfice tube, oil, and to flush condenser really well. The suggestion the last person makes is probably the safest, but seems rather costly, as it sounds almost like replacing the entire A/C system. If money were no object I could replace the whole system by buying a new car.

So how can I check to see if I need a new receiver/dryer or THX?

posted by  kanato

BTW, thanks for your time in replying, much appreciated. And sorry for posting so much :D

I noticed in another someone named pieface said "you cannot replace a compressor yourself it's illegal and you cant legally buy the r-12 for your car," and other people flamed him for other stuff he said in that post. But I'm wondering about what he said about replacing the compressor yourself being illegal; I'm assuming he means that you must have some certification. I've looked into getting EPA Section 609 certification, but that really seems to be for purchasing r-12 or other ozone depleting refrigerants, which aren't what I need. So what's the best source to look up what the rules and regulations are for this sort of thing?

posted by  kanato

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