'87 AC Cycle Time

Interior and Electrical

  1. mgbeda

    mgbeda Member

    Likes Received:
    Jan 31, 2020
    Oxnard, CA
    Thanks to Dr Lebaron and his vacuum hose info I now have WORKING AC! At least it seems to work- it's only been in the 70's so it's not like it's had a tough test. But I'm wondering if the compressor is cycling too much. I timed it and it seems to run about 14 seconds and then shut off for about 10. Does that sound normal, or like it's a little low, or like it's very low? My car is still R12 and I'd hate to hook up a $40 can (if you can find it) only to find out it only needed 2 oz of the stuff.


  2. Aspen500

    Aspen500 Well-Known Member

    Likes Received:
    Feb 14, 2015
    Rib Mountain (Wausau) WI
    At 70 degrees ambient, that cycle time sounds reasonable. The big question is, how cold is the air out the vents? Should be in the high 30's (when it's 95 and humid out, it'd be mid to upper 40's most likely). If there's a sight glass on the dryer, see if there's bubbles. With R-12 a full system should have no (or very few) bubbles. With R134a bubbles are normal since you only use about 80% of the R12 capacity.

    If it was really low you''d not have very cold air and it may cycle every few seconds. The only way to really know if it has the correct amount of refrigerant is to recover what's in there and recharge with the listed capacity. What I mean is, too much refrigerant is as bad, or even worse, than too little.