Posted: 6/20/2007 6:27:40 AM EDT
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I did a search on "air conditioning" in this forum and didn't get any hits so hopefully this isn't a dupe question..... Anyone know of a good diagnostic book on auto air systems for the simple minded  ? The compressor doesn't kick in on my 88 Suburban. I'd like to check at least that part out before I take it somewhere and pay to have it worked on. Thanks, NMSight |
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If you are interested in learning about auto air conditioning in general I would recomend buying a tectbook used by a tech schools automotive program. You can probably get an older revision book for a few bucks, and automotive AC fundamentals haven't changed much in decades, the refrigerants have changed but that is about it. A book like that makes a nice refference for all kinds of problems, it gives you a good breakdown of the principles and concepts of different vehicle systems. It makes it a lot easier to troubleshoot using a servive manual when you have read a primer on the basic concepts, that way you are able to interperet your results, not just hope the FSM is right. |
First thing check the fuse...if it's good you may have a leak and the compressor is cutting out on the low pressure cut out switch. There should be an electrical plug in the refrigerant line somewhere with two wires going to it…pull that plug and put a jumper across the terminals of the plug…if the compressor comes on then it is low on refrigerant. Being an 88 model it should be R-134a you should be able to buy this without the EPA certification…there should be a tag somewhere telling what type it uses and the amount of charge it holds. Look on the underside of the hood and if there is a line of oil above the spot that is over where the compressor is…you have a leak in the front bearing seal…look for oily spots along the refrigerant lines…any greasy spots will be a sign of a leak…check around all the fittings and service ports as well. If you charge it yourself make ABSOLUTLEY SURE you charge it on the low side…if you hook the container to the high side you will be pumping any refrigerant back into the can and can blow it up…usually you can not hook it up to the high side as the service ports are usually different sizes. The low side will be the line that gets cold…it runs from the evaporator coil (the one nearest the firewall) coil back to the compressor…it is larger than the high side line too The condenser coil is the one in front or behind the radiator. Hope this helps ya out. 
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Thanks, I'll check that out when I get home tomorrow. |
Good info there, however I don't think R134a was in use yet in 88. Chances are that by now it has been converted to 134, but from the factory it would have been charged with R12. IF it has any R12 in it, you want to get it out first, then install 134 fitting adaptors and charge with 134. At that age, the vehicle will likely need most of the seals orings replaced anyway. Recharging an AC system after repairing a leak (if it needs refrigerant then it has a leak, which should be repaired to prevent moisture from getting into the system and destroying it), requires running vaccum on the system, which ensures the leak is fixed, and that any moisture in the system has been boiled away and drawn out, this vaccuming will also ensure that all of the R12 is gone. |
Well, I have the line of oil across the hood above the compressor. Also, the info on the system says R-12, although I doubt there is any in there unless it lurks in "cubby holes" in the system. What about pulling a vacuum? What do I need for that? I found a page on the net that shows how to replace the compressor seal. Jumping across the low pressure switch does allow the clutch to engage. I guess I'll change that seal out, then get a can of dye to see how many more leaks there are. Thanks again for all the advice. |