Leaving AC on when turning off engine?
- Thread starter 08t4rUR
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My '03 shuts off the AC but leaves the fan running when the engine is off. Shouldn't be an issue.
SilverRiver
New member
I live in the wet Seattle area so I basically have the AC on 24/7/365. I never turn it off and have never noticed an issue in my Honda or 4Runner.
fullboogie
New member
I don't understand why this is a concern.
Parker1938
Member
Same here but in humid Louisiana. I have never turned the A/C off in 30 years of driving, even when the temperature is turned to heat during the winter. Never had a problem with any vehicle, mostly Toyota.
I know a few people who do this (turn off the A/C before turning off the car) but non of them have ever been able to tell me why. Its always just because that is what their parents did. I never turn my off other than the winter.
Edit: So from my 2 min of research on google it looks like its 1 of 2 reasons why people turn them off. It's either from the old days before cars could disengage the A/C until the car was running causing undo strain on the motor/starter or some do it thinking that it will dry out the evaporator and that in turn will not let mold grow that gives you that nasty smell.
Edit: So from my 2 min of research on google it looks like its 1 of 2 reasons why people turn them off. It's either from the old days before cars could disengage the A/C until the car was running causing undo strain on the motor/starter or some do it thinking that it will dry out the evaporator and that in turn will not let mold grow that gives you that nasty smell.
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riceandpho
Elite Member
I leave 8t on all the time when it's hot, having it on when I remote start my truck far away let's me have a cool inside after all that walking. Also nice to leave it on heat when it's cold out too.
Martinjmpr
New member
That's why I do it. I had that nasty/moldy smell in my old Subaru, took spraying a couple of cans of Lysol into the air intake to get rid of it. After that I got into the habit of switching off the AC a few minutes before shutting off the truck, this allows the ducts to warm up to outside temperature so they don't get condensation in them.
It's not a huge issue here in CO where it's dry, in areas where it's more humid I'd be more concerned.
I'll agree that it's probably not necessary anymore - seems like manufacturers have figured this out and this doesn't seem to be a problem for most people, but I guess I do it out of habit more than anything else. :shrug:
hearno
Senior Member
Lmao, I almost posted this exact question in the 5th gen section today. In my mind, it's easier on the motor to start it without the a/c clutch engaged. The truck probably does that on its own but it doesn't make a difference in how quickly it cools down so I just leave the a/c off until the truck has been running for a few seconds. It's like people that turn their headlights on and then start their vehicle... never understood that.
brianhuntRVA
New member
This and I'm pretty sure they told me to do so when I was learning to drive. My wife thinks I'm crazy but I still do it to this day.
Tell him to mind his own damn business or get somebody else to drive him around next time.
Ha, you are right! The guy is a "know it all" type guy but, i don't let it get to me.
fourwd1
Moderator
Having the AC off before starting the engine lightens the load when starting. Newer vehicles may (or may not) temporarily disable the AC when starting, over the years I've learned to turn the AC off before turning the engine off.
I know my 3 80's trucks won't do it, my 2000 Trooper maybe, and the 2010 Sonata probably.
And I'm moving this to the General discussion section.
I know my 3 80's trucks won't do it, my 2000 Trooper maybe, and the 2010 Sonata probably.
And I'm moving this to the General discussion section.
wadle5
New member
This is exactly what I was going to say. The only reason people used to do it was the strain it put on the initial starting of the vehicle. So it did make sense back then. . . nowadays not as much of an issue
Lester Lugnut
New member
While it may not matter, I shut-off all electrical devices before shutting off the vehicle.
My vehicles make a pronounced "click" a couple of seconds after the engine is running. Some have auto climate control and some have the old school turn the knob and adjust the fan style.
The "click" is the sound of the air compressor clutch engaging. As for the musty smell of the vents, There may actually be another reason for the smell like a plugged drain line that won't let the evaporator drain off.
I've driven cars for years in the hot and humid south and never had a car with the musty smell. If your vehicle has the damp musty smell, I would look closely at the drain lines first.
The "click" is the sound of the air compressor clutch engaging. As for the musty smell of the vents, There may actually be another reason for the smell like a plugged drain line that won't let the evaporator drain off.
I've driven cars for years in the hot and humid south and never had a car with the musty smell. If your vehicle has the damp musty smell, I would look closely at the drain lines first.
SavageRunner
New member
Your friend wouldn't happen to drive a Colorado truck would he? I've heard from a couple owners that leaving it on burns up a relay or something of that sort. May be the same case for Tacoma's too. It's just hearsay so take it with a grain of salt. I have friends with one of each of those and they had to go in and mess with something with the AC to get it to work properly again.
