I have a 1987 Camaro IROC-Z28 with the 350. I started it up in the garage
the other day and let it run for a few minutes. I noticed that it sounded
like the engine was speeding up and then slowing down. When I looked at the
tack I could see that the RPM would be at 1000 and then drop down to 700 for
about 20 seconds and then go back up. I could hear a clicking sound and
figured that it was the air conditioner pump turning on and off. I opened
the hood to verify this. The heater controls were set to defrost, the temp
was on cold, and the fan was on low. This did not occur with the selector
on heat or vent. However when the selector was on defrost, the air
conditioner pump would kick on and off at about 20 second intervals. The
drivers side fan was also cycling on and off. I was just wondering if this
is correct operation. I can't see why the air conditioner should run when
the defroster is turned on. I have had the car for a year and have had no
problems so far. The car only has 18,000 miles on it. I would appreciate
On any of the cars after, say the 60's, the airconditioner will cycle
like that on defrost. This is to help get rid of the moisture on the
inside of the glasses faster, than the old fashion type that would put
out just heater air.
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.