Automotive Air Conditioning Information Forum (Archives)

SD1111 on Sat July 23, 2011 8:49 AM

Year: 93
Make: Honda
Model: Civic DX
Engine Size: 1.5l
Refrigerant Type: R12
Ambient Temp: 95
Country of Origin: United States

My daily commuter 93 Honda Civic DX 1.5l AC has inconsistently cabin cooling. It has been this way every summer since I bought it in 2008. I do not have R12 gages to provide you pressure readings. I have the factory Honda manual and have trouble shot all of the electrical components, and all are functioning correctly, and sending 14 volts to the compressor clutch. The coolant charge seems sufficient, because the system blows good cold air when the compressor is pumping. Last summer, I troubleshot to what I thought was a bad field coil in the front of the compressor. I concluded this diagnosis because there was 12 volts going to the coil, but the clutch would stop engaging after a while. I replaced the field coil (with a used one) and it was better for a little while, but this summer, is just as bad if not worse.

The AC will run good(compressor engaged) at highway for as long as 15 minutes at times, but eventually starts blowing warm (compressor stops pumping). In the city or stop and go, forget it. I finally popped my hood yesterday and found that again the problem appears to be at the compressor. The field coil is getting the 12 volts, but the clutch is not engaging. I thought about buying a new field coil for about $100, but I am now wondering if the compressor itself may be "locking up" or getting tight after pumping for a while, therefore although the field coil has voltage, the clutch is engaging, but the compressor can't spin?

I know I haven't given you much, as far as pressures, but appreciate any opinions or suggestions which I could explore. I am mechanically inclined and have a general-moderate understanding of AC systems. I believe that I have diagnosed the problem to be at the compressor. Thank you for any assistance you can provide. Dave

mk378 on Sat July 23, 2011 9:47 AM

Try to get the clutch plate closer to the pulley. If you already have all the shim washers out you could grind some off of the back of the hub on the plate.

It's not locking up. When a compressor locks up the clutch and/or belt will slip and make a lot of noise and smoke.

SD1111 on Sun July 24, 2011 11:44 AM

OK, I remember their were washers (shims), and there was a set shim dimension required. That will be a fairly simple fix to try, to reduce the shims to the minimum spec. Thanks!! I'll let you know how it turns out.

SD1111 on Sun July 24, 2011 6:13 PM

So here is what I found. Per the OEM service manual, there should be .014"-.028" clearance between the clutch plate & pulley. Mine exceeded the .028. I pulled the only shim washer out, measuring .022", reinstalled the clutch plate and now am within the required specs. I did find that the clutch mating surface had a pretty good coating of grease or oil which appears to be coming from the shaft of the compressor, I cleaned everything real good w/ brake cleaner, reassembled everything, and took her for a test drive.

So far, the compressor is pumping when commanded and has yet to "shut off", as it was doing before, so I believe that mk378 is my hero. I will need to verify that the system cycles, but I know it used to, so suspect it still will. I suspect that with the shaft leak, it may only be a matter of time before more maintenance is required, but if I can get through this smoking hot summer we are experiencing this year, I will be extremely happy. The R12 system is extremely cold, but know at some point my system will require a reburb and R134 will be in order. My car has 223K and still running strong. Averaging 38 MPG since I bought it, 42 MPG the past 6 tanks, so I cannot complain at all.

So thank you mk378 for providing me this quick fix. Hopefully this post will help someone else with a Civic in the future.