Civic AC Compressor

Four years and 40,000 miles after replacing the compressor, expansion valve and receiver dryer on my 95 Civic EX, the compressor blew up witht a half
dollar piece of the housing departing the scene. Last time I replaced a weak compressor, I flushed the system, but I did not replace the condenser. I noticed comments, after doing an extensive search in the archives, that the condenser can't be flushed because of its crossflow design. Also, I had a problem last June with the compressor's head pressure being to high (350 psi), either frome me adding a few onces of R-134A too much or the compressor having some sort of internal malfunction. Prior to my adding 6 oz of refigerant, the car was not cooling properly. I'm wondering if Honda spiral compressors are prone to failure or if not replacing the condenser last time finally caught up with me? Any assistance in this matter would be greatly appreciated.
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Compressor explosion can be caused by overcharge. Overcharge usually doesn't show up as high head pressure (that suggests a problem with the airflow through the condensor), but instead causes the evaporator to overflow and "slug" the compressor with slugs of liquid. The compressor tries to compress the liquid and something's got to give.
I've learned through experience that the stories are true: an R-134a system can't be properly charged by any method except evacuation and filling with a measured amount of refrigerant. I can charge an R-12 system with guages, by ear, by sight glass or by thermometer, but there is something different about R-134a. (The link below suggests it is the reduced total charge makes the margin narrow.) When I tried it by ear and guage, I went completely past the proper point and never saw the cycling settle down, never saw the low side drop... even though I was going very slowly. Then I started hearing little slugs hitting the compressor and I shut it down until a pro could get to it. Sure enough, I was several ounces over and with vacuuming and the proper charge the system worked great. I don't know why 134a reacts that way, but it does. http://www.autoacsystems.com/_faqs/detail/quick.html has a decent description of the situation under the Recharging & Refrigerant section.
Anyway, you can replace the compressor yourself but you should take the car to a pro for the refrigerant side of things.
Mike
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Thanks Mike, you made some very good and informative points. I suppose I should also change the condenser, the expansion valve, and figure out a way to add an in-line filter forward of the compressor? I am very worried about debris migrating to the new compressor which is on order. With all of the Honda's on the road you would think there would be more discussion in this forum about cracked compressor housings. A co-worker told me his wife's 99 Civic cracked its compressor housing. Also, I'm still not totally following what makes the evaporator slug liquid refigerant to the compressor, too much refigerant? Thanks again.
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For the rehabilitation part, that is beyond my experience. I bet you could get free advice from whoever can do the recharge service, though. It may be that the system will have to be flushed to ensure the right amount of oil is added when the compressor is replaced.
Too much refrigerant will slug the compressor, although there are reports of excess oil doing the same. The concept is that in operation the evaporator should stay nearly full of refrigerant without being overfilled. The less full it is the poorer the cooling, but if it is overfull the excess spills into the suction line to the compressor (ouch!). From what I read, even small slugs can damage the valves in the compressor and larger ones can break the compressor housing. Since the refrigerant in the evaporator boils when the compressor is running, the boiling action can splash little drops into the suction line before the level reaches the point where liquid is actually flowing. Tiny splashes are no problem as they evaporate on the warmer metal of the suction line. It's the larger gulps of refrigerant that do the damage.
The situation isn't restricted to Hondas and isn't even specific to R-134a. It's just that it is so much easier to overfill an R-134a system than it was in the days of R-12. As long as the system isn't overfilled it shouldn't be a problem.
My daughter's '93 needs more R-12; after I put my last can in her A/C I am hanging up my guages. I can clearly do more harm than good on the new systems.
Mike
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Michael Pardee wrote:

I'm an air conditioning novice but if a filter were to be attached to the system, shouldn't it be placed on the return line just before the compressor?
TIA
JT
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Thanks again Michael and you're right Grumpy, I should have said upstream of the compressor instead of foward of the compressor.
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