A/C and engine start-up

I was always told as a teenager by my old man to turn off the A/C before shutting off the engine, and more importantly to make sure it was off before
cranking it up to prevent damage (to what?). Can anyone confirm this or is it rumor? I could perhaps see the logic at start-up due to the extra load on the starter, but really, does it make a beans difference?
Mike
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Mike wrote:

I think it's one of those things that probably made sense in it's time but doesn't matter any more. I've never worried about it and never had a problem.
I personally find it annoying that my wife relies on the ignition switch to turn the headlights on and off. My old man said to never start the car with them on.
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Jim Stewart wrote:

Mike,
An additional -- perhaps minor consideration -- is that in some circumstances the moisture that is removed from the air as part of the cooling process can lead to mildew or fungus growth in the evaporator case, with attendant bad odors. Shutting off the A/C but continuing to run the blower fan for a few minutes before shutting the car off (especially when parking for several hours) can reduce the chance of the mildew or fungus growing.
Ed P
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wrote:

I do this all the time on my 97 OB. It provides a "running light" function that the car would otherwise not have. On many cars the headlamps are turned off automatically when the starter motor is on - not sure if that happens on my OB.
-- Vic Roberts Replace xxx with vdr in e-mail address.
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The major benefit I can see with leaving off the AC at startup is to keep the load off the battery after startup. All cars today disable the AC during startup but as soon as you release the key the AC will kick on and therefore put a heavy load on the battery...therefore give you electrical system a break...
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On 29 May 2005 16:48:31 -0700, " snipped-for-privacy@etolivia.com"

How does the AC load the battery? There is an electrically actuated clutch, but the compressor is driven by the engine.
-- Vic Roberts Replace xxx with vdr in e-mail address.
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the battery runs the starter, which turns the engine which now has extra load on it b/c of the A/C pump.
wrote:

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Battery/Generator/Alternator produce electricity. While the engine is idling after starting, the alternator does not generate enough power to recover the loss from starting the engine, also does not generate enough power to run everything: 1. AC requires a electrically actuated clutch, that actuation is a solenoid that uses a lot of power, that solenoid continues to draw power as long as the clutch is actuated!!!!!!!!!! 2. Dual electric fans on the radiator are running to draw air through the radiator. 3. Your inside fan is running as well to cool the interior of the car. This list does not include stuff like fuel system, ECU, etc........
Therefore give the battery a break!!!!!!
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Not only the clutch, but the radiator fan and the heater system fan are activated as well.
wrote:

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