I always shut down all accessories before turning the vehicle off. Good luck getting the woman in your life to do that. Even though I told her a dozen times- everything including a loud radio comes on as soon as the key is turned.
Turn A/C off first before shutting off engine?
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My wife shuts it off, I don't. My wife shuts everything off. AC, radio, fan, even turns the temperature control to cold. My Camry has climate control. The AC doesn't start cranking right at start-up. It takes about 30 seconds after the engine starts until the AC and fan crank up.
I try to turn the VENT on about 3 miles from home. Gives the system a chance to dry up and not so much water dripping in the garage. YMMV.
GrtArtiste
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Originally Posted By: Indydriver
Originally Posted By: mightymousetech
I always turn off my A/C several minutes before shutting the car off. I hate the smell when the evap is left damp and bacteria grows in there.
But can you get your wife to do the same?
How to explain also, there is no need to slam the door
Originally Posted By: mightymousetech
I always turn off my A/C several minutes before shutting the car off. I hate the smell when the evap is left damp and bacteria grows in there.
But can you get your wife to do the same?
How to explain also, there is no need to slam the door
Originally Posted By: Indydriver
Originally Posted By: mightymousetech
I always turn off my A/C several minutes before shutting the car off. I hate the smell when the evap is left damp and bacteria grows in there.
But can you get your wife to do the same?
Yes. She will do the same.
Originally Posted By: mightymousetech
I always turn off my A/C several minutes before shutting the car off. I hate the smell when the evap is left damp and bacteria grows in there.
But can you get your wife to do the same?
Yes. She will do the same.
From what I think I know.
Many newer GM vehicles have a hidden feature in the body computer called "after blow". [no this isn't a cigarette]. When turned on, "after blow" will continue to run the climate control fan for a couple of minutes if you shut the engine down with AC on. Supposedly this is to dry out the evaporator core and prevent the formation of mold and odours. A Tech2 scan tool is needed to access this feature. I have older cars so I try to shut the AC off just before I get home.
Most modern cars don't cycle their AC compressors as the compressors are variable displacement and in times of low demand the stroke of the compressor is reduced to almost nothing but the clutch stays engaged.
Many newer GM vehicles have a hidden feature in the body computer called "after blow". [no this isn't a cigarette]. When turned on, "after blow" will continue to run the climate control fan for a couple of minutes if you shut the engine down with AC on. Supposedly this is to dry out the evaporator core and prevent the formation of mold and odours. A Tech2 scan tool is needed to access this feature. I have older cars so I try to shut the AC off just before I get home.
Most modern cars don't cycle their AC compressors as the compressors are variable displacement and in times of low demand the stroke of the compressor is reduced to almost nothing but the clutch stays engaged.
I shut NOTHING off when I turn the car off except the headlights if it doesn't have autolamps. Radio, AC, Heat, blower, etc. It's all on at all times. Unless it's one of those odd cars (old VW's?) that doesn't shut it off with the key, it will make no difference to that stuff if it's running or not at crank time as it all goes off anyway.
Turning that stuff on/off is way too fiddly.
Turning that stuff on/off is way too fiddly.
AZjeff
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Everything off before shutdown, always have. Also all flotsam and jetsam removed from the interior on last exit of the day. After 37 years TOWMBO does both automatically too.
Originally Posted By: itguy08
I shut NOTHING off when I turn the car off except the headlights if it doesn't have autolamps. Radio, AC, Heat, blower, etc. It's all on at all times. Unless it's one of those odd cars (old VW's?) that doesn't shut it off with the key, it will make no difference to that stuff if it's running or not at crank time as it all goes off anyway.
Turning that stuff on/off is way too fiddly.
Yeah, I just hit the button and it shuts everything off. The A/C light comes on automatically once you hit auto on the climate control. Even in the winter. I've got a weird A/C compressor though, Mercedes makes variable ratio compressors so there's no actual clutch. Takes a few seconds for it to kick in after you start the car.
I shut NOTHING off when I turn the car off except the headlights if it doesn't have autolamps. Radio, AC, Heat, blower, etc. It's all on at all times. Unless it's one of those odd cars (old VW's?) that doesn't shut it off with the key, it will make no difference to that stuff if it's running or not at crank time as it all goes off anyway.
Turning that stuff on/off is way too fiddly.
Yeah, I just hit the button and it shuts everything off. The A/C light comes on automatically once you hit auto on the climate control. Even in the winter. I've got a weird A/C compressor though, Mercedes makes variable ratio compressors so there's no actual clutch. Takes a few seconds for it to kick in after you start the car.
My wife and I turn ours off but not the fan as we get into our neighborhood.
Originally Posted By: DBMaster
I am in the habit of doing it, too. But, it's because my dad told me that if I didn't I would be forcing the starter to turn the A/C compressor when I restarted the engine. This was on a 1972 Pontiac
The compressor won't/can't build ANY pressure cranking speeds, so no drag.
Originally Posted By: Johnny2Bad
I normally turn everything off before shutdown, I want a clean start with minimal electrical load and where I can hear the motor and mechanicals before getting underway (to listen for any unusual sounds/noises). A/C would be no different.
I thought so, too - - - but on my F150, the engine starts and runs for at least 10 seconds before the computer turns the a/c on
I am in the habit of doing it, too. But, it's because my dad told me that if I didn't I would be forcing the starter to turn the A/C compressor when I restarted the engine. This was on a 1972 Pontiac
The compressor won't/can't build ANY pressure cranking speeds, so no drag.
Originally Posted By: Johnny2Bad
I normally turn everything off before shutdown, I want a clean start with minimal electrical load and where I can hear the motor and mechanicals before getting underway (to listen for any unusual sounds/noises). A/C would be no different.
I thought so, too - - - but on my F150, the engine starts and runs for at least 10 seconds before the computer turns the a/c on
On todays cars, the AC compressor is NOT on when you start the car. It takes several seconds before engagement. As for shut off, I never let a little puddle of water bother me. Never had any AC problems.
I stopped shutting the climate control off after I got my 1970 Cadillac. My last vehicle [Town Car] the a/c system was on for 12 years and 315K miles. The Tahoe was been on since the day I brought it home.
It is stupid to shut if off every time you stop IMHO. If it is raining [or your in the south in jungle humidity] your windows will fog up upon starting your vehicle. If you leave the system on all the time no fogging. BTW I get zero smell from the a/c system unlike the people that shut off the a/c every time they stop.
BTW none of my vehicles every needed a/c work. Just set it and forget it.
All that is just IMHO. To each their own.
It is stupid to shut if off every time you stop IMHO. If it is raining [or your in the south in jungle humidity] your windows will fog up upon starting your vehicle. If you leave the system on all the time no fogging. BTW I get zero smell from the a/c system unlike the people that shut off the a/c every time they stop.
BTW none of my vehicles every needed a/c work. Just set it and forget it.
All that is just IMHO. To each their own.
Originally Posted By: Johnny2Bad
I normally turn everything off before shutdown, I want a clean start with minimal electrical load and where I can hear the motor and mechanicals before getting underway (to listen for any unusual sounds/noises). A/C would be no different.
This is what I do.
I normally turn everything off before shutdown, I want a clean start with minimal electrical load and where I can hear the motor and mechanicals before getting underway (to listen for any unusual sounds/noises). A/C would be no different.
This is what I do.
Originally Posted By: 69GTX
I figure turning the AC off a few minutes before stopping the car gives the water droplets in the engine bay a chance to evaporate quickly. In any case, I don't want the AC running as soon as I start the car next time. For one, depending on your starting rpm in fast idle (1500-2000 rpm+) your AC compressor spins right up from 0 to higher rpm. The only thing worse is turning it on when at highway speeds (2500+ rpm). Surely this is not ideal for compressor longevity. I'd much rather turn on my AC when the car is at low idle (800-1100 rpm). It will then ramp up with engine speed.
That's exactly what the clutch is doing when you drive on the highway with the AC on, thousands of times. There's a relay which in most cars cuts out the compresser when cranking. Old wives tales die hard.
I figure turning the AC off a few minutes before stopping the car gives the water droplets in the engine bay a chance to evaporate quickly. In any case, I don't want the AC running as soon as I start the car next time. For one, depending on your starting rpm in fast idle (1500-2000 rpm+) your AC compressor spins right up from 0 to higher rpm. The only thing worse is turning it on when at highway speeds (2500+ rpm). Surely this is not ideal for compressor longevity. I'd much rather turn on my AC when the car is at low idle (800-1100 rpm). It will then ramp up with engine speed.
That's exactly what the clutch is doing when you drive on the highway with the AC on, thousands of times. There's a relay which in most cars cuts out the compresser when cranking. Old wives tales die hard.
AC compressors do not start up when you start your engine. They kick in a couple of moments after the engine is running. These are not the same large compressors of the 60's and 70's. Today's automatic climate control uses the AC in a lot of ways so you may not know it's even running.
thanks for the comments on variable displacement compressors--I was breaking-in the new Audi last 2 weeks in really hot weather and was marveling at the job the Germans did on a/c compressor engagement--so smooth you never know when it's on or off. Now I know why I am not hearing the thud/clunk when the compressor engages.
Maybe I'll stick around another decade or two--who knows what they'll come with next
Steve
Maybe I'll stick around another decade or two--who knows what they'll come with next
Steve
I don't have horrible OCD and my cars have long, full lives.
I don't turn squat off when I'm starting or stopping my cars.
I don't turn squat off when I'm starting or stopping my cars.
Originally Posted By: PimTac
AC compressors do not start up when you start your engine. They kick in a couple of moments after the engine is running. These are not the same large compressors of the 60's and 70's. Today's automatic climate control uses the AC in a lot of ways so you may not know it's even running.
That's a good point about automatic climate control.
AC compressors do not start up when you start your engine. They kick in a couple of moments after the engine is running. These are not the same large compressors of the 60's and 70's. Today's automatic climate control uses the AC in a lot of ways so you may not know it's even running.
That's a good point about automatic climate control.
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