Hi I recently bought this 72 Skylark, 350, that is an A/C car but not working and I am trying to get it going. I have the wiring all figured out now but as I understand it I need to plug this superheat wire into the back of the compressor. The wire was there (hanging) but I see nowhere to plug it into the compressor. I attached some pictures. So if there really is nowhere to plug that wire in can this setup still work? (I see this says it and Olds compressor so maybe they differ?) thanks - this is a great group! -Dan
Yes, the system will work with that wire disconnected. You just won't have protection for the compressor if you lose the refrigerant. GM cars prior to about 1971-72 didnt use the switch and thermal fuse so it's really not a big deal. What all are you doing to resurrect the system on your car?
Lots of the a/c wires were cut/mangled and I have a partially melted thermal limiter. I also was missing some of the a/c hoses. I have them all now. I am figuring I can get all the wires and hoses hooked up and buy some autozone refrigerant and see what happens. I'm not an a/c guy but I know a little and I've had some luck doing this on other cars. I know I should get the system evacuated, etc...
That's a good start, but there's more to it than that. - Since the systen was open to atmosphere, there is a good likelihood of internal corrosion in the evaporator, condenser and metal lines. You will need to to solvent flush the system to check for that. If there is corrosion in any of those parts, they will need to be replaced. Spiders also love the small openings in those parts. Flushing will also remove any old oil oil from the heat exchangers, along with any spider nests. -The expansion valve inlet screen should be checked for debris and cleaned. Testing the valve would also be a good idea. -The oil in the compressor has been exposed to atmosphere for some time. You need to drain and oil flush the compressor. You then need to install oil that is compatible with the refrigerant you plan to use. The A6 compressor has an oil sump, so it's much like changing the oil in your lawn mower. -Since you are using R134a, the POA valve should be tested and calibrated for R134a. It will "work" with the factory setting, but adjusting it for R134a can make a big difference in performance. Taking these steps can make the difference between success and failure. One stray spider nest or some internal corrosion plugging the expansion valve can ruin your day after spending hours and $$ reassembling the system. One other thing that you want to consider. All of the air that has ever entered that system was pulled, unfiltered, through the evaporator. Its, not uncommon for the evaporator to be caked with dirt, organic matter, etc. Rodent nests are common in that area, too. This restricts airflow and can cause all manner of unpleasant smells once the AC is working. It's a PITA, but you might think about removing the evaporator cover on the firewall and cleaning out the evaporator case. With the system disassembled, now is the time to do it. Good Luck!
I'm trying to get a lot of things done on this car for next weekend so yeah I was cutting corners. Ordinarily I'd take it to a shop but I don't have the time now. I did have the heater core out and the heater box was cleaned out and the A/C box looked ok from the duct. Maybe there's a little more I can do myself. Found this: http://www.buickperformance.com/ac.htm Is there a particular solvent I should use or is there a specific product I should use? I don't think I've seen all of these lubes and flushes at pep boys/autozone. thanks for the advice.
That's a good, well written article. :Comp: I've seen it before and often point folks to it. With the heater core out you are looking at the "clean" side of the evaporator. All of the crud is on the opposite side. Where you can't see it, of course. Pulling the evap case is a real judgement call. Sometimes they're clean inside, but I've seen more nasty ones than clean ones. There is an AC flush solvent called DURA-141 that is preferred. It's pricy but it works best. You can also use good lacquer thinner with proper safety precautions. Whatever you use must be fully evaporating and residue free. You need access to LOTS of compressed air for flushing.
Ok it didn't work I bought a system flush from autozone, from "medium weight" oil, and 4 12 oz cans of R134A - I also replaced most of the O rings with green ones. Flushed out all the lines and compressor the best I could and put it all together. I discovered the lower hose which has the "can" that i got from a yard was too long. I pulled it from a full size '71 buick. I had to make a loop from the can to the condensor (doesn't look good). I ran the A/C and started filling it. (pump did engage) That's when I noticed the POA to compressor hose had a leak. It would be nice to know I have the correct lower compressor hose/can and get the other hose fixed but I'd have to find a place that can hook me up and most likely take off from work which probably won't happen any time soon. At least I got the power top pump replaced and working, the master cylinder replaced and got my wife's car to stop overheating :beer
There are a few highly recommended places online that can rebuild your hoses for you. You can trim the too long hose somewhere in the middle, route it where you want it, and mark the two halves where they would fit together so that the fittings can be installed on the new hose properly. Check out ACKits.com, Old Air Products and Classic Auto Air. You might be able to find someone locally that can do it, but in my area there is no one that can rebuild old lines without messing them up. I really hope you flushed the compressor with refrigerant OIL. You should never flush a compressor with flush solvent. You drain and fill the compressor sump with oil then rotate the compressor about 10 times. Repeat that process 3 times. Was that flush solvent from AZ the FJC brand? I tried the FJC flush some years back and it was nearly impossible to get it all out of the system. It was like a water based soap mixture! You really need an aromatic solvent that will fully evaporate, like DURA-141 or lacquer thinner. Anything else will contaminate the oil and can harm the compressor. AZ also sells a flush in an aerosol can, but it's pretty darn worthless. It seems to be the right solvent, but there's not nearly enough to do the job and you still need to dry the system with compressed air. To properly flush an AC system takes roughly 1 gallon of solvent and a large amount of compressed air. You didn't mention pulling a vacuum on the system. (That would have also clued you in on the hose leak). Pulling the system into a hard vacuum is critical. Air and moisture in an AC system is a killer. I'm certainly not trying to be an a****le, but I wonder if that leaky hose may have saved you from bigger problems and/or much more expense. Much like building a motor or trans, cutting corners on an AC system can be costly in the long run. (Unlike a motor or trans, you can cut your losses and walk away and still drive the car without AC. o No Myself and other guys on the forum can help you through the process of repairing/rebuilding your AC system. It's not "hard" but you have to be thorough and pretty meticulous, and it can get pricy. I usually suggest that folks budget $800-1K to get their GM POA system up and working well (DIY). If/when the cost is less, sometimes MUCH less, be happy and divert the remainder back to your bank account or car fund. Taking it to a shop is an option, but you need to find a shop that is familiar with older GM POA systems and has experience with repairing/rebuilding systems that have been out of commission for a long time. Age brings a lot of factors to the table that many shops aren't prepared to deal with. Many Techs, even in dedicated cooling system/AC shops, weren't even born yet when when the last POA systems were built. Shops also charge by the hour. My local Independent shop rate is about $65-75/hr. That can easily add up to $2.5K or more, parts and labor, on a POA system that has been inoperative and open for 10, 20, or more years. Again, I'm not trying to be an A***ole, know it all. I'm just trying to give you a realistic idea of what it will take to make your AC system work right again. Best of luck, Tom
