A/C on off question

[MaraSport]

Some people told me that I should turn my a/c to the off position before I cut the car off... They also said that I shouldn't turn the a/c on until the car has been started...

IS ALL THAT NECESSARY OR IS IT JUST "B.S."?

Thanks yal...

[BAS]

Re: A/C on off question

Probably not all "BS".

On my 94, I can tell some drag either voltage wise
or from the AC compressor clutch.

On my 2002 Cavalier, It appears there is no
voltage going to the AC compressor, because I
notice less drain.

Anyways, I turn off my AC on my 94, because
it is harder to start with it , and does place an
extra drain on the battery which isn't necessary
when starting up.

Originally posted by MaraSport
Some people told me that I should turn my a/c to the off position before I cut the car off... They also said that I shouldn't turn the a/c on until the car has been started...

IS ALL THAT NECESSARY OR IS IT JUST "B.S."?

Thanks yal...

[MN6WS6]

Actually it's more BS than truth. When I start my 96 with the AC on, you hear the clutch engage then disengage. The compressor "sees" that the pulley is not turning, disenganges itself, then will not turn on while the car is cranking because it is on an accessory lead that is disengaged while the car is actually in "start" position. If you listen, or have somebody else crank your car, you will see what I mean. When you turn the key on, the compressor engages, then within a second disengages. You start the car, then it is at least 1-2 seconds before the compressor engages again. There is no load on the motor while in start position. GM did it this way for this exact reason, because we all know that everybody leaves their AC on when they get out of the car (especially in the south). In the newest of cars, with automatic climate control, the compressor actually will not engage at all until after the car has been running for like 3 seconds.

[MaraSport]

Hay thanks yal...

Hay thanks... I live in NC, so I was worried, but if it disengages it self then I shouldn't worry... Unlike my import, my maro starts right up with the a/c on but my import would just spin its starter for a little before it catches and starts... So, I was worried that my maro was doing damage to its starter because it starts so easily...

Thanks yal...

[Christopherrr]

Actually, if you listen closely, when you start the car (with the AC engaged)...the AC isn't even on...it's not until the car has started and idled when the AC cuts on. Also, if you accelerate...above 3000-3500 RPM, take notice how your AC cuts off! I noticed when I accelerated to pass a car and heard the AC compressor refilling up (that gas in the lines sound)...I was like "pretty cool". Our cars are actually smarter than you think...

[Joe K. 99 Zeee!!]

This would be applicable for an older car. Maybe late 60's or so. On cars from the '70's or newer the clutch for the A/C compressor will not engage when you're starting the engine. It comes on a few seconds after the engine is started. This is a feature that was added some time ago to preven current drain while starting the engine. I remember reading about this from an old (around 1970) sales brochure.

In addition, when you got to wide open throttle the compressor will shut down to increase horsepower output. You may have noticed this on your older car when you were accelerating to get on the highway and warm air would come from the vents even though the A/C was on.

Both these features were added a long time ago. So the advice is right in a way, but it's out of date on newer cars.

[Christopherrr]

LoL...I noticed it on the TA because I never drove a car that wasn't rude crude or loud...you notice much more when everything around is quiet...sorta.

[MaraSport]

Thanks Yal...

Thanks Yal...
I was curious since the person that told me that was my uncle and he has a pontiac grand am 199? model year...
But that is amazing that the a/c doesn't even come on for a few seconds after the car is started...

LATER...