Husband disagrees w/ wife:
Wife believes the inertial force of engaging AC at speed damages the compressor, the belt, and/or the engine. Ray says there is some merit to this. But isn’t the AC compressor cycling on and off whenever the AC is on, speed or idle?
It would be more rpm based then mph based…
Regardless, I will use my AC anytime I am hot, and remember that when you turn on your defrost, it turns on the AC compressor to help defrost/dehumidify the frost/fog on the windshield… plus it keeps the compressor from lying dormient and the seals drying up, so it is better to use the compressor then to not use it, and since a lot of AC systems go well over 100K-200K + miles, I am not worried about it…
System is designed to handle all normal use, tun it on whenever you want.
Initial compressor clutch engagement for the day can be harsh due to refrigerant oil from the lines settling into the compressor. Some vehicles alleviate the hash “clunk” by engaging the compressor clutch during start-up while cranking the engine (less than 400 rpms).
The harsh engagement shouldn’t harm the compressor, but I prefer to switch the system on while at idle.
Why do I get so much argument when I explain the above, on other car forums and blogs? The other participants typically insist that the compressor engages only for aircon, and not for defogger, simply because the blower doors direct the air differently for the two different modes.
And don’t tell me it’s “how I go about explaining it”, because there’s just no gettn through stupid in some circles.