Over Heats With Air Conditioning
Copyright 2000 Frank Zemaitis/STE, ltd. All Rights Reserved

I had a problem where the Z would overheat at idle on hot days and only with the AC on.  Also the AC would not cool very well on the road and especially at idle.  There is probably more that one answer for this one.  However I corrected my overheat at idle problem at the car wash.  On a whim one 90 Saturday while I was washing my car, I decided to break out the ratchet set and remove my fan cowling. ack washed the radiator, starting at one end and slowly sprayed every inch of the radiator.  I also repeated the process from the frthe condenser.  It was amazing how much debris came out of the radiator and condenser.  There were bits of leaves and clumps of cottonwood lint and who knows what on the ground.  I put the cowling back on and hit the road.  To my surprise the AC was blowing cold!  I mean freezing!  When I got home I let the Z idle in the drive for 10 minutes or so.  When I checked the temp gage it was smack dab in the middle!  Normally it would have slowly crept up near the top of the gage.  Evidently a small amount of debris blocking the radiator is not enough to cause overheating at highway or city speeds.  At high RPM there is enough air volume to provide sufficient cooling.  But at idle RPM the air flow is weak enough to be overcome by debris.