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Two Things My Dad Taught Me - Valid?

Hey, so ever since I was a youngin’, I’ve been doing two things my dad taught me. But nobody else I know even considers these things: am I crazy???

Habit One: I turn off the air conditioner about ten seconds before I turn off the car. Running on just the fan until the air warms up to ambient temperature gets the moisture out of the system, so your car can sit happily, corrosion free, until you need to drive again.

Habit Two: Every time I start my engine, I let it warm up before I shut it off. An example of this would be, if I need to move my car a few feet to open a parking space, I won’t just move it real quick. I will move it, then apply moderate throttle for a few minutes until I see the temperature come up. The theory here is that shutting down an engine while it’s cold leaves moisture inside, which is bad?

-shut off A/C early? OK, more to prevent any mold rather than corrosion
-warm up? Not needed if this is only occaisoinal, and just having the temp come up may still not be enough to dry out the oil.

Unnecessary on both counts.

No reason to do either one.

I think the air is a good idea but you need to drive it at least 5-10 mi AFTER it is hot to get ride of the moisture and that is my 2 cents LOL

You should increase the time for number 1 too about 5 minutes. I have no opinion on number 2.

I used to install what were called “afterblow” kits that kept the blower running for 20 min after engine shutdown. This kit was put on problem cars that you could not get rid of odor for an acceptable time period. Kits came from GM.

Habit one: If you need your AC to last a 100 years, it might help. I have seen car AC systems go 30 years without doing this. I have to admit that I did this with cars from the 60’s, but I don’t remember why. I don’t do it today.

Habit two: This would be a good idea if the vehicle is not used very often or is going into long term storage. It was probably more valid in your dads day due to carburetors, not so much with todays fuel injection motors.

I don’t do either of these things with my car.

Revving a cold engine is bad for it.

I may be half as old as your dad, but I still feel the compulsion to turn off the ac 30 seconds before I stop. I know this may have been relevant to some cars long ago, and in todays cars it seems to make no difference but I do it anyway. Same for habit 2. Probably not valid for anything produced after 1988

Niether one needed.

I seriously doubt that 10 seconds are enough to dry the air conditioner evaporator coil. I don’t know how long it would require nor do I know if it is necessary but it might be worth a try to prevent mold odor from happening.

Regarding the engine warmup; you might want to extend that to a 10 mile drive to warm and dry the exhaust system. I just traded a 13 year old car with the original exhaust so it works for me and I live in winter road salt country.

Diesel owners have this thing about turning off their engines. They just hate to do it. They think the rest of us like the smell and the noise as much as they do…

Lion9Car, key word I used was “moderate” throttle. I don’t think there’s any debate that moderate throttle is a much better way to heat up an engine than letting it idle.

I practice #1 almost religiously to minimize mold although I turn it off with enough time that it’s blowing ambient temps right before shutdown. Never had a mold smell in any of my cars. Hard to prove a negative though.

On my daily drivers, I’ll start and move them without concern. They get used enough to burn off any condensate the next time they’re run.

On stored cars, I will briefly start and run them to move. If it takes any more than 30-60 seconds of running, I let them warm up before shutting down.

"practice #1 almost religiously to minimize mold although I turn it off with enough time that it’s blowing ambient temps right before shutdown. Never had a mold smell in any of my cars. Hard to prove a negative though. "

I never turn my AC off, ever. I’ve never had a mold smell or issue in any of my cars for the combined several 100K miles that I have put on them. I live in a hot and humid area.

Maybe that’s the key, you use yours constantly. I know alot of people who complain about foul smelling A/C systems around here. In this area, they probably aren’t used as frequently and that may allow stuff an opportunity to grow.