Air conditioner etiquette

GEORGE GREEN 5280

MEMBER
1992 FORD AEROSTAR
6 CYL

I've got my air conditioner working and the air coming out is cold now. It's a good repair but I don't want to be too rough on the system because although it's not super fragile, it's not indestructible either.

Many years ago I heard a couple of things about air conditioners which may or may not be true.

First, I heard that turning the air conditioner on at highway speed (55 mph) is hard on the system. Is this true?

Second, I heard that turning the air conditioner on and off over short periods of time is hard on the system. One example would be waiting in a fast food restaurant drive thru line and shutting the engine off while waiting, then restarting it each time the line moves forward to save gas. Is this hard on the air conditioning system?

Help!

2 Replies

CARADIODOC

MECHANIC
33,741 POSTS

Not really. Whatever you can do, the engineers took that into account when they designed the system. Many systems cycle the clutch on and off while you're driving at highway speed. That is how the pressures are regulated. Some systems today have variable displacement compressors that stay engaged all the time you have it turned on. They will just kind of idle along until more refrigerant is needed inside the van, then they increase their pumping rate. If you turn them off periodically, they will just work that much harder to catch up when you turn them back on.

Be aware that the compressor will also run in winter when you have the defroster on. That is to remove humidity from the air before it gets blown onto the cold windshield where it would condense and cause fogging.