I drive an 89 s10 blazer with a 4.3l v6 engine with AC. I noticed that when i start the truck and leave the heater on, i hear a ticking noise from the hood. Examining under the hood, i noticed the disk on the ac clutch keeps spinning and stop abruptly. this is the disk spinning. Disk Spinning

and this is the disk stopped disk stopped

is this normal? The serpentine belt does spin without any issue.

1 Answer 1


From what you have described, you are seeing (and hearing) the AC compressor turning on and off. This is normal on most vehicles when the heating selector is set to defrost the windshield. They designed it so the AC can assist in removing moisture from the air to help defrost more quickly.

If this is happening all the time, no matter what the heat selector is set to, you may want to have the AC system serviced.


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