A/C help please!

[danzo]

Don't know if anyone here is well-versed in a/c mechanics, but I'm stumped. Today I installed a new compressor as the FSM told me the old one was caput. The manifold gauges read the same (about 60psi each) when I tried to fill it with 134a. The rebuilt compressor also gives the same manifold readings, and it wouldn't even suck in half of a 12oz can of refrigerant. I did pour 3 oz of the specified oil into the comp and 3 oz into the reciever/dryer as per the shop who sold me the compressor. Incidentally it is a huge, well-regarded local shop called Austin-Baker.

The FSM is telling me that equal gauge readings mean a bad comp, but I have a tough time accepting a freshly rebuilt one doesn't work with 0 hours on it. The old comp was not the original, I got it from someone here and had it tested at Austin-Baker. They said it was compressing, but leaking and wouldn't last very long, thus the rebuild.

Thanks for any help, it sucks driving in 95F heat with no a/c. Living down south I feel I should know more about this sort of thing, but when I was young and spritely I didn't so much care for the "luxuries of the fat 'n' sassy" like I do now.

[arbskynxnex]

I'm not well versed, but maybe a blockage somewhere in the system?

From what little I did (and so long ago) work on refigerators, the site below seems to have some good info.

http://www.aa1car.com/library/ac98.htm

[Petros]

It has been a while since I did A/C work, but I seem to remember to get a full charge of refrigerant you had to purge all the air out of the system while you were filling it, takes a vac pump on the low pressure side running at the same time you are filling it from the other. If you do not get the air out of the system you will not be able to put all the refrigerant in.

Also, it seems to be if you got refrigerant in the system, you have to run it for a while to know if it is working. You are supposed to have liquid refrigerant in half the system, and gas in the other. That can only happen when the compressor has been running for a while, and may not happen at all if you do not have enough refrigerant in the system. There is perhaps not enough to condense into a liquid in the condenser (the part up front next to the radiator), which means it will not vaporize in the evaporator (the part under the dash), which is how it cools the air in the car.

[danzo]

Man do I feel like the Three Stooges all wrapped into one! After realizing that the high/low gauge readings on my car seemed reversed, I checked the lines. Turns out I had hooked the low gauge to the high side and vice versa. So I simply corrected the prob and now have cold a/c!! I feel like Mr. Carnegie and should prolly move out of my neigborhood to avoid retaliation from other neighbors. Hopefully they will understqand.

I should point out that a quality a/c shop is your best friend - I bought the 134 retrofit kit from Autozone, but this is garbage. The a/c shop has the 134a fittings that don't use your old OEM schrader valves, which is what you need to simplify things and elliminate a point of failure. The AZ adapters don't seal, but the a/c shop ones do. Four bucks times two well spent!

Thanks for the suggestions.

[splatterdog]

Sorry I couldn't help you sooner, been a little inactive lately. I hope things continue to work out. It does sounds like a very dirty retro took place however. Did you replace the reciever/drier at least? And at the very least pull a deep vacuum for at least 30 minutes before charging? A proper retro involves flushing the system with expensive solvent and a new reciever/driver/accumulator...

Better yet would have been to keep it R12.

Make sure to wash any dirt or bugs off the condenser! Those and rads are like air filters and can hold a lot more crud than meets the eye.

I would also suggest NOT using any ac sealants. It might sound like a good idea, but the only real fix after it's put in is total system replacement. The ONLY time I would consider using it would be on a 10 hour evaporator job on a nearly worn out car. The T4 doesn't qualify in that nearly the entire car could be replaced in 10 hours or so.

[danzo]

No prob, splatter. I did r/r the dryer, and did pull a vacuum a few months ago. I know this doesn't mean much after the system has been opened again, but if it starts to fail again I will do another vac. Didn't use any sealant, just straight 134 and replaced the convenient o-rings. R12 is deaux, keep it 134 is the plan. Condensor is very clean, but I might cleaner it as per your tip. If it works for the rest of the summer I'm happy, then I'll decide what to do.

Thanks a bunch for the suggestions, like I said I don't know as much as I should about a/c systems. BTW, both of my cars remained un-flipped in light of the Mavericks win, not that I care about hoops.