Killing Engine With Ac On

Song · August 22, 2007

I had a AC guy tell me, years ago, that you need to cut your AC off before killing the engine. Is this true?

StoneyPgh · August 22, 2007

I had a AC guy tell me, years ago, that you need to cut your AC off before killing the engine. Is this true?

Back in the old days, this advice was given so that the engine wouldn't be started with the A/C left on. Guess that would be bad for the compressor.

Roofer · August 22, 2007

I always turn the AC off and idle for a few minutes before I shut down the motor. It lets my diesel cool a little before I shut it off.

BigJayDogg3 · August 23, 2007

I read elsewhere on here that about 5 min before you get to your destination, to turn off the A/C and let the fan blow. It is supposed to dry out the condenser (I think), so you don't have microscopic pets blowing in your face, and creating an odor. I don't do this but 2 or 3 times a week since I have heard this, and my odor problems seem to be going away.

asilverblazer · August 23, 2007

I heard it was to create less work for the engine to start back up. But me, its hot, I like the cool air right up til time to jump out and run inside before the sweat breaks out.

dewfpo · August 23, 2007

From a compressor standpoint, it's not necessary. If you leave the A/C on, the compressor whon't be allowed to kick in until a certain number of seconds after the engine starts. The ECM lets the engine stabilize before it loads the A/C compressor. In the old days, there was no ECM and the compressor didn't cycle it ran all the time. So you'd be cranking the A/C compressor over with the engine if it were turned on.

But.... from a mildew standpoint, in some climates (mine), I turn off the A/C compressor about 2 miles from home but leave the fan funning to dry out the evaporator. Otherwise I get that musty smell on startup.

DEWFPO

tranetech · August 25, 2007

ttt

KTSTEEL · August 25, 2007

If you do have that musty smell on startup of the A/C, how do get rid of it?

BigJayDogg3 · August 25, 2007

There is stuff you can buy from GM and I am sure there are some others that you can buy that aren't from them. But before I bought anything I would try drying out and see if that helps to keep money in my pocket. I know for me, when I discovered this method, and tried it, it got rid of my odor, but it may just be dumb luck that it happened like that for me. Good Luck getting rid of your odor problem.