The compressor and dryer have been replaced, PAG 46 oil 5 oz added, vacuumed an hour, pressure has no change at -30 psi for another hour after stop, vacuumed 45 minutes again, added R-134A in 2 cans. The clutch didn't engage at all, using paper clip for the relay (pins 30+87) to force compressor on while adding refrigerant, which was working because I felt frozen cold on the low pressure line. However, it still doesn't work with the relay(new) and the pressure on both side is about 85 and 90 psi when using paper clip to force it engaged. Too little difference between the low and high lines. Please help for any possible reasons!

  • Honda Civic needs 23 oz of R134a, I added 2 cans with line purging, which should be the right amount.
    – Ray
    Commented Feb 19, 2017 at 1:23
  • Now using paper clip can force the clutch engaged but no cold air coming out any more. Is that too much refrigerant or not enough?
    – Ray
    Commented Feb 19, 2017 at 1:28
  • 1
    23oz should work OK. Are you sure the the clutch actually engages? Relay failures are super common on this era Honda. Commented Feb 19, 2017 at 3:01
  • Have you checked the clutch on the compressor - - you say you force the relay closed - have you got a supply there and does it get to the compressor?
    – Solar Mike
    Commented Feb 19, 2017 at 9:16
  • The clutch surely engages when I use paper clip to connect port 30 to 87 instead of using relay but there's no cooling air coming out. The relay works when exchanges with one for condenser fan. These two relays look same. Any more idea? Thanks much!
    – Ray
    Commented Feb 19, 2017 at 10:50

1 Answer 1


If clutch is engaging(forced)and hi and low side pressures are similar the most likely explanation is that the TX valve has failed. Pressure variation yesterday to today will be brought about by change in ambient temperature.

  • I have had the expansion valve coming with the new compressor but it seems very difficult to replace it because it's inside of the cabin. Anyway, Possibly I will have to try. By the way, based on other readings, if there's a clog the high side pressure would be too high and the low side too low; if the low side is unexpectedly too high and the high side too low (this is the case), there's a problem with the compressor. Is this correct? Thanks much for the help!
    – Ray
    Commented Feb 19, 2017 at 13:34
  • The pressures are 65 and 70 psi this morning compared to 85 and 90 yesterday. Does it mean leaking somewhere? Please help!
    – Ray
    Commented Feb 19, 2017 at 16:11
  • Is it possible to blow up the compressor by adding Freon too fast?
    – Ray
    Commented Feb 21, 2017 at 1:28
  • The low pressure line was freezing cold while adding the second half can by forcing the compressor on. After the second can added, it doesn't work any more, which is really weird.
    – Ray
    Commented Feb 21, 2017 at 1:38

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