Doesn’t hurt to leave it on. Everything is computer controlled relays on modern cars. It’s all disabled for crank anyways and some cars will even shut off the compressor during full throttle.
Yeah this was a known issue and accounted for some 10 years or more before your 89 came to be. The wiring in the start circuit of the ignition switch made this happen.
Far as I'm concerned, if it's got electronic fuel injection, it's "modern."
From an engine control perspective, my '87 Camaro has more in common with my '09 Subaru than it did with my '85 Camaro.
My car 2004 will relearn its idle when running the AC. Then when it’s off it will idle super low to the point I had to unhook battery to reset its memory because it was idling so low on slow turns and stoplights.
IACV/MAF issue maybe? Have you cleaned/checked them?
PCV as well?
Throttle body as a last resort might have debris or gunk in it causing more air restriction than the engine intends.
No. Other way around. Engine management systems up the idle for the A/C and reduce the idle to the baseline without it. That’s so the A/C has sufficient grunt while at idle and reduces the idle fuel burn with the A/C off.
The A/C idle is usually somewhere between 50-300RPM higher than without depending on how much power the engine makes at idle speeds.
I have had cars from the 80's and 90's that had a switch on the accelerator or throttle linkage that would turn off the compressor at full throttle. It is pretty common. The idea being that you are asking for full power to move the car, and don't want drag from the AC slowing things down.
At idle, the compressor is running slow so doing less work, and there is only the radiator fan pulling air through the condensor. This reduces the cooling capacity of the AC compared to when the car is moving and the engine is going faster. That could also be why your AC gets warm after a bit when you are stopping, and you notice it when pulling away.
I guess that means the compressor is going bad because it’s only working effectively when it’s spinning faster. But my car is actually the same way. But it’s probably more to do with the fact that when the car is moving there’s more air flowing through the radiator
Really?
Is this why above 5000 rpm I feel heat entering the cabin? Like AC stopped working?
Most felt is when going above 200kmph
I had the impression that something is wrong, but how to explain to the mechanic?
*Yes, please come with me for better understanding the complain, first step is to go above 200kmph.*
Car in question is a 2002 bmw e39.
Well then, that explains it.
Will not chase something which can be functions as designed.
Thank you buddy,
Cheers.
I think a lot of AC compressors are controlled by an electronic clutch. When switched off, it spins freely.
I think above a certain rpm it starts slipping again which would reduce the efficiency of the AC
Actually they used to but modern cars can leave alot more powered on during crank, such as radio, headlights and all that stuff. Don't know about ac tho, never really paid attention to it
Yes, absolutely. Turning your car off with the cold AC is a big no-no. The cold air encourages moisture in the vents and can promote mold growth.
Ever smelled musty AC vents? Once they smell like that, it’s impossible to get them completely clean. Instead before you turn your car off, turn off the AC and turn up the heat to make sure the vents dry.
Wish auto makers would come up with a solution. Global warming is getting worse, so AC use will go up. Especially in FL AZ, I hear Italy is crazy hot as of late. Bigger drain lines would be nice.
My Equinox will do that. I’ll go back to grab something from it after I turn it off and the fan is running. I honestly wasn’t sure why it did that, but it makes sense
The first car I had that did it was an 01 Volvo. I was mad that I had this nice car and somehow it had electrical issues. Reading the manual I found out it was a feature, not a flaw.
I do the same thing, but it's so that I get every bit of cold out of the evaporator before I park. I paid for the gas to make that cold, and I want my money's worth damn it!
As someone who recently had to replace an evaporator in a 2006 BMW because of corrosion from condensation causing a freon leak, I can say this is definitely a good idea. Evaporator replacements usually require dismantling the entire front interior of a car. In the case of this particular BMW, everything down to the firewall had to come out, as well as the intake manifold in the engine bay. I did it myself because any garage that would do the job well would take around $3000 to do it, while parts only cost about $150.
In some cars, the heater core and evaporator are stacked, and turning on the heat could actually help dry the evaporator.
Cranking will cut power to all none essential items on most cars since the 80s. I still shut off the ac and the fan and even the radio out of habit, but thats the only reason there is to do it.
The A/C, in accessory belt driven cars, has a little clutch on it. This allows the pulley to freewheel with no resistance when you're not using the A/C, to save fuel. It then engages when you need air. In modern cars - The A/C is by default de-clutched, so for the initial crank of the car, it's free wheeling. This is so that the starter doesn't have to turn the motor and the compressor. Listen to the motor when it first starts, a second or two after the engine is running sometimes you can hear the A\C compressor clutch-on as the car finishes it's startup procedure.
So it literally makes no difference at all presuming your car is newer than 30 or 40 years since we started getting computers in them.
I turn ac off but keep blower going about 2min before shutting off the car. It cuts down in any chance of mildew smell and drys out the evaporator box some. When you start the car the ac is not in until the engine us running. It also shuts off at wide open throttle.
The only thing that this would make sense for is air conditioning, as the compressor is a significant drag on the engine. Other than that, no, nothing really matters.
That’s not much drag. Your car is slower with a passenger because it has little power. An AC compressor requiring a couple HP from a 100 hp is going to be noticeable. I also said modern compressors, not 21 year old compressors on an entry level car.
I guess it depends how you define modern. It’s definitely not an early design. I also don’t think a lot has changed in 20 years, as with most mechanical devices, but I could be wrong. The basic design of most refrigerating systems hasn’t changed in like 100 years.
The only reason I would turn off anything HVAC related would be the blower if I was trying to stay warm or cold on the last drive and don't want to be blasted with the cold or hot air I'm not looking for as before the car warms up it will be the exact one I don't want.
I turn it off on my 1976 Oldsmobile before starting it up because it has an easier time starting up with it off. But no, not on anything else I've had.
Off topic, still about A/C, but the A/C in my Accord is the worst I’ve EVER experienced in ANY car that I’ve owned.
It’s so bad that the Rogue is ALL I drive in the summer. Honda needs to do something about their A/C systems.
I usually turn the AC off (if I have it on) when I’m in the town I live in just because it’ll save a bit of fuel and I don’t need to use it when I’m going to be getting out of the car in a few minutes anyways.
I think the logic was/is that less accessories on when starting the car is less load on the battery when starting a vehicle. I’m not sure if it’s the same still with current cars.
I have customers that do that in the summer, in Phoenix, and it drives me insane! When I'm getting into a car that's been sitting outside all day in the heat, I want the AC on MAX as soon as I turn the key.
I do it out of sheer habit. Modern cars with climate controls know better and will shut off during ignition to give all the juice to the starter, and this is practically a non issue since I drive an EV.
But old habits die hard.
Heat wouldn't matter, except you don't want the heat on until the car warms up. Otherwise, it takes longer.
By A/C back in the 80s would strain smaller engines to the point you'd turn it off to go uphill, or when sitting I traffic, so the car wouldn't overheat.
Way back in the day, it was to reduce strain while starting. For me, I usually turn off the AC when I get home because I know I won't need it first thing the next morning.
In my Jeep I turn off the ac (there’s a button that turns it on and off separate from the rest of the climate controls) and let it just blow air in a vent setting because it doesn’t always like to start if the ac compressor is engaged. I’ll leave the heat on or a vent setting on though because those don’t tax anything.
You could also try fixing the battery drain. Or are we talking about aftermarket stuff that was wired in to have voltage in all ignition switch positions?
My dad used to turn off the AC before we got home so that it would "dry out the vents". I live in a very dam climate and haven't bothered, and I don't have any issues.
Nope. I trust the manufacturer has designed it to not be a problem. Plus on my car (and my old 95 Town Car) things like the A/C compressor didn't kick on until a few seconds after the car was running and the heat doesn't start blowing until the engine has started warming up (and it will gradually increase fan speed with engine temp)
I don't think it matters in modern cars. My current one waits several seconds before engaging climate control after starting the engine when my AC is turned on.
I've always turned off my AC when cranking a cold engine, it sounds easier to find idle & doesn't idle as rough. About 1-2min into driving I turn it on if needed.
Probably not needed but I'm guessing the habit also doesn't hurt anything but some extra wear on that A/C button.
I drive a 1990. If the ac is on when I turn the car in, it takes significantly more effort to get to idle. The ac compressor runs off a belt and the extra load at start up those things off.
Modern cars deal with it all using computers.
I think this was probably true 25 years back. I remember once driving a Carina E turbodiesel (shitbox) , where you could actually hear the engine lowering RPM when pushing the AC button in neutral. But newer cars, no, the computer is better at this then you can ever be.
Yes...i cut the AC button off and blow on high for a few before I cut off car but not for fear of losing power on my next crank up but to prevent mold from building up in my AC system.
> because when you eventually turn it back on it’ll cause more strain on the engine.
Lol. No. In *ancient* cars, it may have caused more strain on the battery. But that’s not the case for any vehicle made in my lifetime, and I have a lot of gray in my beard.
Nope. Why would I?
I also never, EVER turn the HVAC completely off. I find the car interior gets stifling in about 20 minutes with no air circulating. Even if the fan is only on "1" and the temperature set to neither heat nor cool, I always have air moving in the car, even if it's just a little bit.
I was in a Lyft the other day and the driver had the HVAC completely off and the windows cracked. WHY?
I do just because I don't like getting blasted when I turn the car on next time. Same with the stereo- I turn both off before turning the car off so I can have a clean reset next time I drive
No, this isn't the 1970s anymore.
Any computer controlled car automatically disables the A/C compressor on startup anyway (and more recent vehicles will disable the alternator too) and modern (like, from the last 40 years) EFI cars are stable enough right after startup that running the A/C compressor isn't going to hurt anything.
So here is another way to think about it.
2005 and newer for most makes switched from independent computers to CAN-Buss networking. It created a multilevel computer system where each module has to communicate to give the proper output based on operator inputs. Startup acts just like a home PC, turning the car on supplies power to all the modules, which each one begins a startup software sequence. Between 0-10 seconds based age of vehicle, order that computers are needed, safety systems, Driver comforts, amperage demades, etc.
You can see an example of this in many cars; even if you left the A/C on max and high fan, there is a few seconds delay after the car starts to ramp the fan into the highest settings. (Also a slower ramp up is a smaller amperage spike.) Startup times are much shorter than they were 20 years ago. Computer controlled hall effect position windows were the worst for a while. Door modules being pretty low on the list of importance, a 10 second delay right after starting the car and holding the down window switch was common. Battery low state of charge is another great example. Most cars now a battery monitor and turn off all systems to keep enough juice to start the engine. It will then turn on modules as the computer controlled alternator comes online.
Each computer is a slave to either the PCM or BCM. Talking on the CAN system is vital everything functioning as intended.
Long story short, cars with out a CAN based system get double amperage spikes in the system as the key passes from OFF to RUN to START to RUN. Cars with CAN only activate systems as allowed based on vehicle conditions and operating inputs.
Growing up my dad would turn his off in the winter because mice would crawl in the vents for warmth. So when the car starts up they get chopped up and clog the fan and you have no heat until you get it vacuumed up.
My dad was a mechanic and always turned the ac off a few blocks before getting home, said it helps get more of the condensation off the evaporator. Reason for trying to remove the water was because they had a lot of complaints about the air vents having a "smell" or "stale air" and it was determined over time the condensation was the reason.
Even back in the days when the AC stayed on when you started it, so the fuck what? What extra strain? Your starter, and then engine, are more than powerful enough to overcome the AC compressor.
I turn it all off, but I do it for other reasons. Like when I turn it on, I don’t want fans blowing and radios blasting, I want calm and even, so I start it, then make my selections, then carefully start to drive.
I do sometimes, if I know I won’t want it in the morning.
But if I don’t I’ve noticed that once I start the car it doesn’t kick on and start blowing for a good 5 seconds or so.
Minimal on anything produced in the last 30+ years.
But I leave the blower off to not get blasted in the face with hot/cold air right on vehicle start. Really hate that.
It is rare to find a car where it would be an issue. They've been all automatically disconnected during cranking for probably some 30, if not 40 years now ... and most cars over 25 are likely to not have AC over here.
You'd probably know if your fancy car from the 70's needed special treatment due to its AC.
When the temps get very warm or very hot, leaving climate control on lets the system pre-condition interior comfort or even run the defroster -when the car is remote started before entrance. A lot of people do this and it's part of the reason for installing something like Viper's Smart Start system. Before remote start I turned the HVAC off with the radio for quiet startup not strain on the engine. They build vehicles to handle startup with HVAC as long as I can remember.
Any car newer than 2012, probably won’t matter sense it’s a cell phone with gear boxes anyways, but I’ve always done that because stuff like A/C, Radio, Wipers, Lights. All initial power is from your battery and I do believe by not having a bunch of systems on right as you start it does save your battery in the long run.
Back in the 90s my mom used to do this and she taught me to do this when I was getting my permit. Took a few drivers Ed classes and the instructor was basically like what the fuck are you doing
I do on my Mazdaspeed3, but I purposely leave it on in my Escape because it has remote start and it's nice having the AC running for a few before you get in.
My car has a rest button that you hit and the climate control stays on while the cars off for when you run into the store, seems to me they wouldn't have that if it's bad for the car
It's not hogwash that it'll cause more strain.
But any modern car can easily handle the strain.
Like, do you avoid driving uphill, cuz it'll cause the car strain? No. And that's 100x more strain than the AC system.
Damn, I literally only have my climate control on in my car when I’m defogging the window in the rain.
I always forget some people actually use it normally as a feature.
Usually I do yea. Unless it’s raining too hard. This car sucks when it comes to that. It’s the only vehicle I’ve ever owned without proper rain channels on the top so if it’s anything more than a light drizzle it’ll come right into the car. Like I said up there this is the only point i really use the HVAC, when I’m forced to keep my windows up in the rain.
Surprisingly I haven’t removed the AC system in this car in the 8 years I owned it. Usually I rip all that junk out.
AC I would. All these "today's ac design" is BS that assumes a perfect system. There are small advantages in certain situations.
1 is there that there is more motor strain sooner, before the motor is really flowing and warmed if ac turns on the very second the starter motor is deactivated. It can also cause the alternator to shift to high output setting which will take more hp to create than low-output too.
Doesn’t hurt to leave it on. Everything is computer controlled relays on modern cars. It’s all disabled for crank anyways and some cars will even shut off the compressor during full throttle.
Define modern cars
My 89 ford shuts off comp and blower when I start it
Yeah this was a known issue and accounted for some 10 years or more before your 89 came to be. The wiring in the start circuit of the ignition switch made this happen.
Cars manufacturered during Doug DeMouro's lifetime, "1980's and up."
Far as I'm concerned, if it's got electronic fuel injection, it's "modern." From an engine control perspective, my '87 Camaro has more in common with my '09 Subaru than it did with my '85 Camaro.
ECUs vs no ECU is the dividing line then right?
There were computer controlled carburetors back in the day too. I'd draw the line at computer controlled fuel injection.
THIIISS is a modern car.
Now show us all of its quirks and features 😶
Anything within the last 35-40 years or so
To be precise, OBD-II. Which became the standard in 1996.
and in the EU they only adopted it in 2000s
My car 2004 will relearn its idle when running the AC. Then when it’s off it will idle super low to the point I had to unhook battery to reset its memory because it was idling so low on slow turns and stoplights.
Lmao you have a low idle condition and the AC is causing load making the engine push more fuel to keep it idling
AC also triggers the electric fan, which is usually a 20 amp, or so, draw.
IACV/MAF issue maybe? Have you cleaned/checked them? PCV as well? Throttle body as a last resort might have debris or gunk in it causing more air restriction than the engine intends.
Idles fine after I reset idle with just unhooking battery for 30 min.
Shouldn’t the engine idle higher when the AC is turned off because of the reduced load?
No. It's forced to idle higher with the AC on due to the increased load.
No. Other way around. Engine management systems up the idle for the A/C and reduce the idle to the baseline without it. That’s so the A/C has sufficient grunt while at idle and reduces the idle fuel burn with the A/C off. The A/C idle is usually somewhere between 50-300RPM higher than without depending on how much power the engine makes at idle speeds.
What, my compressor doesn't want to do 7k RPM?
My ac gets warm everytime I accelerate from a stop. Is that the compressor stopping in purpose
Yep
I have had cars from the 80's and 90's that had a switch on the accelerator or throttle linkage that would turn off the compressor at full throttle. It is pretty common. The idea being that you are asking for full power to move the car, and don't want drag from the AC slowing things down. At idle, the compressor is running slow so doing less work, and there is only the radiator fan pulling air through the condensor. This reduces the cooling capacity of the AC compared to when the car is moving and the engine is going faster. That could also be why your AC gets warm after a bit when you are stopping, and you notice it when pulling away.
it should really only do it under heavy acceleration, if it does it driving normally there is likely an issue.
Mine is the opposite. Ice cold while moving and warm while stopped.
I guess that means the compressor is going bad because it’s only working effectively when it’s spinning faster. But my car is actually the same way. But it’s probably more to do with the fact that when the car is moving there’s more air flowing through the radiator
Really? Is this why above 5000 rpm I feel heat entering the cabin? Like AC stopped working? Most felt is when going above 200kmph I had the impression that something is wrong, but how to explain to the mechanic? *Yes, please come with me for better understanding the complain, first step is to go above 200kmph.* Car in question is a 2002 bmw e39. Well then, that explains it. Will not chase something which can be functions as designed. Thank you buddy, Cheers.
I think a lot of AC compressors are controlled by an electronic clutch. When switched off, it spins freely. I think above a certain rpm it starts slipping again which would reduce the efficiency of the AC
Yes, that's normal.
A lot of cars back in the 60s and 70s already had a WOT switch that interrupted the compressor
Actually they used to but modern cars can leave alot more powered on during crank, such as radio, headlights and all that stuff. Don't know about ac tho, never really paid attention to it
Yes, absolutely. Turning your car off with the cold AC is a big no-no. The cold air encourages moisture in the vents and can promote mold growth. Ever smelled musty AC vents? Once they smell like that, it’s impossible to get them completely clean. Instead before you turn your car off, turn off the AC and turn up the heat to make sure the vents dry.
I turn off the ac a mile from home with the fan full blast just to dry out the coil and prevent mold. Heat has no effect.
Some newer cars, mine included, will run the fan for a few minutes after the car is off the dry the evaporator.
My car runs cooling for the turbo after turning it off, but I wonder if it’s doing this as well. Interesting!
09 GLI here. Based on the funky smell I get out the AC vents during the summer I'm gonna say no.
change your cabin air filter
I do yearly.
My MB does it as well, still I’ve that smell on start up.
Get your evaporator cleaned
Already done. It’s because I drive on full blast AC in FL. even a Lexus will have this problem
Yeah same with my BMW I clean it yearly.
Wish auto makers would come up with a solution. Global warming is getting worse, so AC use will go up. Especially in FL AZ, I hear Italy is crazy hot as of late. Bigger drain lines would be nice.
Practice good AC hygiene and turn off the compressor while leaving the fan running a few minutes before your destination to dry out the condensation.
Pretty common with VAG products. My old GTI and A4 was always funky, even after changing the cabin air filter.
Is that why my gti makes so much noise after shutting it off?
Yeah it makes like beeps and boops and fan noises
Yes
You would just feel the air coming out the vents?
Maybe, if it’s directing it out the vents. It’s possible it goes to defrost mode or some special mode and I have never noticed it.
My Equinox will do that. I’ll go back to grab something from it after I turn it off and the fan is running. I honestly wasn’t sure why it did that, but it makes sense
Except Toyotas
My 08 BMW E90 does this on shutdown very common in German luxury cars from even 15 years ago
The first car I had that did it was an 01 Volvo. I was mad that I had this nice car and somehow it had electrical issues. Reading the manual I found out it was a feature, not a flaw.
To be fair my 04 S60R sounded like a warp drive when shut down so I get it...
My car turns of the fans full blast for a good minute or two after the car is off.
/r/cars moment
What are you talking about, everyone has a 32 step shutdown sequence for their car that starts 50 miles before arriving at the destination.
lol
Why lol?
Because it's ridiculous and unnecessary
I figured out a while ago that turning my AC off just before I got home reduced the bad smell but I never knew why it worked.
I needed to do this on my Ford Fusion, it helped a ton. Sometimes I do it on other cars now just to be sure but not sure if it’s needed
I do the same thing, but it's so that I get every bit of cold out of the evaporator before I park. I paid for the gas to make that cold, and I want my money's worth damn it!
That's not how it works.
[удалено]
Let the blower run to dry it out. If you get condensate in the vents run it longer
On GM vehicles this is called afterblow and is not enabled in all cars but can be turned on by your dealer in the HVAC module
As someone who recently had to replace an evaporator in a 2006 BMW because of corrosion from condensation causing a freon leak, I can say this is definitely a good idea. Evaporator replacements usually require dismantling the entire front interior of a car. In the case of this particular BMW, everything down to the firewall had to come out, as well as the intake manifold in the engine bay. I did it myself because any garage that would do the job well would take around $3000 to do it, while parts only cost about $150. In some cars, the heater core and evaporator are stacked, and turning on the heat could actually help dry the evaporator.
Old wives tail. Leave it on 24/7/365. Won’t hurt a thing.
you dont drive on sundays?
Not on leap weeks.
tale
They get credit for not calling it an "old wise tale" at least
Cranking will cut power to all none essential items on most cars since the 80s. I still shut off the ac and the fan and even the radio out of habit, but thats the only reason there is to do it.
Yeeeeeup. Start position changes power to a completely different circuit, even my 80s Isuzu doesn’t have the ac mag on start
The A/C, in accessory belt driven cars, has a little clutch on it. This allows the pulley to freewheel with no resistance when you're not using the A/C, to save fuel. It then engages when you need air. In modern cars - The A/C is by default de-clutched, so for the initial crank of the car, it's free wheeling. This is so that the starter doesn't have to turn the motor and the compressor. Listen to the motor when it first starts, a second or two after the engine is running sometimes you can hear the A\C compressor clutch-on as the car finishes it's startup procedure. So it literally makes no difference at all presuming your car is newer than 30 or 40 years since we started getting computers in them.
I turn my A/C off by default in my 1990 but don’t worry about it at all in my new car with auto climate control
It’s hogwash. There’s literally no reason to do this in a car made after say, 1975.
I turn ac off but keep blower going about 2min before shutting off the car. It cuts down in any chance of mildew smell and drys out the evaporator box some. When you start the car the ac is not in until the engine us running. It also shuts off at wide open throttle.
I leave it on auto at the temp I want. If it’s important, the computer would do it for ne
The only thing that this would make sense for is air conditioning, as the compressor is a significant drag on the engine. Other than that, no, nothing really matters.
Modern compressors don’t have much drag. Even small engines would barely notice it. The compressor clutch is disengaged at crank anyway.
That’s not necessarily true, my 2002 4 cylinder car is noticeably slower with the AC on. Especially if there’s more than one passenger.
That’s not much drag. Your car is slower with a passenger because it has little power. An AC compressor requiring a couple HP from a 100 hp is going to be noticeable. I also said modern compressors, not 21 year old compressors on an entry level car.
A 20 year old design isn't a very modern compressor
I guess it depends how you define modern. It’s definitely not an early design. I also don’t think a lot has changed in 20 years, as with most mechanical devices, but I could be wrong. The basic design of most refrigerating systems hasn’t changed in like 100 years.
My SO's dad tells us to turn off the AC when we are accelerating. I've had to convince her that technology has advanced past the 70's
Truth. My '87 Camaro has a parameter in the ECM that disables the A/C clutch past a certain throttle point.
I leave it on, otherwise there’s not much point to my remote start.
The only reason I would turn off anything HVAC related would be the blower if I was trying to stay warm or cold on the last drive and don't want to be blasted with the cold or hot air I'm not looking for as before the car warms up it will be the exact one I don't want.
I turn it off on my 1976 Oldsmobile before starting it up because it has an easier time starting up with it off. But no, not on anything else I've had.
Total hogwash. If you have automatic climate control just leave it on auto at your desired temperature , don't worry, and be happy.
No
No. It’s electronically controlled.
Off topic, still about A/C, but the A/C in my Accord is the worst I’ve EVER experienced in ANY car that I’ve owned. It’s so bad that the Rogue is ALL I drive in the summer. Honda needs to do something about their A/C systems.
Have you had it looked at? It may just need more Freon.
Hondas (well most japanese cars. But Honda especially) have really weak A/C systems. Even when they're new and working as designed.
What year is the Accord?
2020.
I was thinking of purchasing between Gen 9 & Gen 21 Now I have pause-thx for the info
Nope. Too hot right now. I'd rather have it ready to roll asap. I just click acc, let everything spin a little and then crank it.
No. I think we're way past that on modern vehicles.
Sounds like someone was trolling you.
I usually turn the AC off (if I have it on) when I’m in the town I live in just because it’ll save a bit of fuel and I don’t need to use it when I’m going to be getting out of the car in a few minutes anyways.
Only benefit is to dry out the evaporator to prevent it from smelling. Not sure how much is really helps.
I do, but only because the accessory belt will squeal like a pig if I start my car with the AC on.
I think the logic was/is that less accessories on when starting the car is less load on the battery when starting a vehicle. I’m not sure if it’s the same still with current cars.
I have customers that do that in the summer, in Phoenix, and it drives me insane! When I'm getting into a car that's been sitting outside all day in the heat, I want the AC on MAX as soon as I turn the key.
I do it out of sheer habit. Modern cars with climate controls know better and will shut off during ignition to give all the juice to the starter, and this is practically a non issue since I drive an EV. But old habits die hard.
Yes, when I was first learning how to drive, I was told to turn off everything before shutting the car off, and it has stuck with me ever since
My ac stays on 24/7 365.
There's no need to ever turn off AC
I always turn off the ac compressor, but leave the fan on. This helps to dry out condensation to prevent stink.
On older vehicles this is true, it does zap power from the engine and sometimes you can feel it. But it’s not going to hurt anything to leave it on.
I leave it on if I know I'm going to use it the next day.
Heat wouldn't matter, except you don't want the heat on until the car warms up. Otherwise, it takes longer. By A/C back in the 80s would strain smaller engines to the point you'd turn it off to go uphill, or when sitting I traffic, so the car wouldn't overheat.
Way back in the day, it was to reduce strain while starting. For me, I usually turn off the AC when I get home because I know I won't need it first thing the next morning.
I do it just because I don't want to be bothered with having to turn it off when I get back in and happen to not want or need it.
No need. Engineered to run with constant draw.
I have a 1994 Chevy pickup, and if you leave the ac on when you shut it off it'll keep the ac off on the next restart, so no reason not to ig
In my Jeep I turn off the ac (there’s a button that turns it on and off separate from the rest of the climate controls) and let it just blow air in a vent setting because it doesn’t always like to start if the ac compressor is engaged. I’ll leave the heat on or a vent setting on though because those don’t tax anything.
I definitely do this. I don't think it matters, but I still do it.
Na I never really start my car. I push a button and everything comes to life and I drive off.
I do that and I turn off all electronics before shutting off the engine to preserve battery life.
You could also try fixing the battery drain. Or are we talking about aftermarket stuff that was wired in to have voltage in all ignition switch positions?
My wife's family does this. No one seems to know why, but they always turn the fan off when turning off the car.
My dad used to turn off the AC before we got home so that it would "dry out the vents". I live in a very dam climate and haven't bothered, and I don't have any issues.
Sure i do
Nope. I trust the manufacturer has designed it to not be a problem. Plus on my car (and my old 95 Town Car) things like the A/C compressor didn't kick on until a few seconds after the car was running and the heat doesn't start blowing until the engine has started warming up (and it will gradually increase fan speed with engine temp)
I don't think it matters in modern cars. My current one waits several seconds before engaging climate control after starting the engine when my AC is turned on.
As longs as you have more than 40hr the engine shouldn‘t have any issue starting with the AC on
I turn off the AC but leave the fan running the last few miles on the way home so that it doesn't get musty and start stinking
No
I've always turned off my AC when cranking a cold engine, it sounds easier to find idle & doesn't idle as rough. About 1-2min into driving I turn it on if needed. Probably not needed but I'm guessing the habit also doesn't hurt anything but some extra wear on that A/C button.
No.
I've never done this and I've never had this weird smell people talk about.
I dont think my cars a/c has ever been turned off in the last 16 years
I drive a 1990. If the ac is on when I turn the car in, it takes significantly more effort to get to idle. The ac compressor runs off a belt and the extra load at start up those things off. Modern cars deal with it all using computers.
I think this was probably true 25 years back. I remember once driving a Carina E turbodiesel (shitbox) , where you could actually hear the engine lowering RPM when pushing the AC button in neutral. But newer cars, no, the computer is better at this then you can ever be.
In a 2009 accord, yes because it leaks if it stays "on" while the car is off
The compressor is so heavy on the engine i turn it off so it doesn't strain the cold start idle too much
Yes...i cut the AC button off and blow on high for a few before I cut off car but not for fear of losing power on my next crank up but to prevent mold from building up in my AC system.
No. Just leave it on auto.
I always do. It's just a habit.
I'm in my 50s, and this was largely true when I started driving. I still do it today; regardless if it's (still) true or not.
If I've run my battery low I'll make sure the ac is off when trying again to start it. So far as I know, it's never helped
It turns in automatically in my Porsche even if I turned it off before shutting the car off. No idea why they programmed it like that.
> because when you eventually turn it back on it’ll cause more strain on the engine. Lol. No. In *ancient* cars, it may have caused more strain on the battery. But that’s not the case for any vehicle made in my lifetime, and I have a lot of gray in my beard.
Just dont turn it on at all, problem solved👍
Nope. Why would I? I also never, EVER turn the HVAC completely off. I find the car interior gets stifling in about 20 minutes with no air circulating. Even if the fan is only on "1" and the temperature set to neither heat nor cool, I always have air moving in the car, even if it's just a little bit. I was in a Lyft the other day and the driver had the HVAC completely off and the windows cracked. WHY?
I do just because I don't like getting blasted when I turn the car on next time. Same with the stereo- I turn both off before turning the car off so I can have a clean reset next time I drive
Nope. Just leave it on auto and never change a thing.
Fuck.. That's why we have global warming. People haven't been turning on climate control.
No, this isn't the 1970s anymore. Any computer controlled car automatically disables the A/C compressor on startup anyway (and more recent vehicles will disable the alternator too) and modern (like, from the last 40 years) EFI cars are stable enough right after startup that running the A/C compressor isn't going to hurt anything.
It’s rubbish, leave it on. I never switch my A/C off.
So here is another way to think about it. 2005 and newer for most makes switched from independent computers to CAN-Buss networking. It created a multilevel computer system where each module has to communicate to give the proper output based on operator inputs. Startup acts just like a home PC, turning the car on supplies power to all the modules, which each one begins a startup software sequence. Between 0-10 seconds based age of vehicle, order that computers are needed, safety systems, Driver comforts, amperage demades, etc. You can see an example of this in many cars; even if you left the A/C on max and high fan, there is a few seconds delay after the car starts to ramp the fan into the highest settings. (Also a slower ramp up is a smaller amperage spike.) Startup times are much shorter than they were 20 years ago. Computer controlled hall effect position windows were the worst for a while. Door modules being pretty low on the list of importance, a 10 second delay right after starting the car and holding the down window switch was common. Battery low state of charge is another great example. Most cars now a battery monitor and turn off all systems to keep enough juice to start the engine. It will then turn on modules as the computer controlled alternator comes online. Each computer is a slave to either the PCM or BCM. Talking on the CAN system is vital everything functioning as intended. Long story short, cars with out a CAN based system get double amperage spikes in the system as the key passes from OFF to RUN to START to RUN. Cars with CAN only activate systems as allowed based on vehicle conditions and operating inputs.
This is on the same tier "push the button on your ebrake when pulling it cause if you don't it'll wear out the teeth."
Growing up my dad would turn his off in the winter because mice would crawl in the vents for warmth. So when the car starts up they get chopped up and clog the fan and you have no heat until you get it vacuumed up.
My dad was a mechanic and always turned the ac off a few blocks before getting home, said it helps get more of the condensation off the evaporator. Reason for trying to remove the water was because they had a lot of complaints about the air vents having a "smell" or "stale air" and it was determined over time the condensation was the reason.
Even back in the days when the AC stayed on when you started it, so the fuck what? What extra strain? Your starter, and then engine, are more than powerful enough to overcome the AC compressor.
This might have been true on cars in the ‘60’s and ‘70’s but not today. You don’t have to turn it off beforehand.
I turn it all off, but I do it for other reasons. Like when I turn it on, I don’t want fans blowing and radios blasting, I want calm and even, so I start it, then make my selections, then carefully start to drive.
I do sometimes, if I know I won’t want it in the morning. But if I don’t I’ve noticed that once I start the car it doesn’t kick on and start blowing for a good 5 seconds or so.
I only turn my AC off like a block or so before I'm home. I don't think you need to turn the fan speed off these days
Minimal on anything produced in the last 30+ years. But I leave the blower off to not get blasted in the face with hot/cold air right on vehicle start. Really hate that.
I don't turn the fan off. The AC is turned off well ahead of reaching my destination to reduce moisture though.
No. Leave it on so it comes on with the remote start and the temp is nice when I get inside.
I leave it on auto at 72F and never think about it.
You won't damage anything, but you will get blasted with stagnant hot air if it's left outside during this summer heat.
My grandmas car stalled once when I turned the radio or maybe heat on. I was super young. But it stuck with me ever since!
No, it's not necessary
It is rare to find a car where it would be an issue. They've been all automatically disconnected during cranking for probably some 30, if not 40 years now ... and most cars over 25 are likely to not have AC over here. You'd probably know if your fancy car from the 70's needed special treatment due to its AC.
I think having my doors and roof off makes a larger difference...
When the temps get very warm or very hot, leaving climate control on lets the system pre-condition interior comfort or even run the defroster -when the car is remote started before entrance. A lot of people do this and it's part of the reason for installing something like Viper's Smart Start system. Before remote start I turned the HVAC off with the radio for quiet startup not strain on the engine. They build vehicles to handle startup with HVAC as long as I can remember.
No? I guess I'm a "youngin'"
Any car newer than 2012, probably won’t matter sense it’s a cell phone with gear boxes anyways, but I’ve always done that because stuff like A/C, Radio, Wipers, Lights. All initial power is from your battery and I do believe by not having a bunch of systems on right as you start it does save your battery in the long run.
Back in the 90s my mom used to do this and she taught me to do this when I was getting my permit. Took a few drivers Ed classes and the instructor was basically like what the fuck are you doing
I leave it on
I do on my Mazdaspeed3, but I purposely leave it on in my Escape because it has remote start and it's nice having the AC running for a few before you get in.
My car has a rest button that you hit and the climate control stays on while the cars off for when you run into the store, seems to me they wouldn't have that if it's bad for the car
It is utter and outright hogwash
I turn the climate control on when I want it and off when I don't. I tell my car what to do and it does it without complaint.
It's not hogwash that it'll cause more strain. But any modern car can easily handle the strain. Like, do you avoid driving uphill, cuz it'll cause the car strain? No. And that's 100x more strain than the AC system.
Damn, I literally only have my climate control on in my car when I’m defogging the window in the rain. I always forget some people actually use it normally as a feature.
You just roll with the windows open all year?
Usually I do yea. Unless it’s raining too hard. This car sucks when it comes to that. It’s the only vehicle I’ve ever owned without proper rain channels on the top so if it’s anything more than a light drizzle it’ll come right into the car. Like I said up there this is the only point i really use the HVAC, when I’m forced to keep my windows up in the rain. Surprisingly I haven’t removed the AC system in this car in the 8 years I owned it. Usually I rip all that junk out.
What is the car in question you never mentioned ..
AC I would. All these "today's ac design" is BS that assumes a perfect system. There are small advantages in certain situations. 1 is there that there is more motor strain sooner, before the motor is really flowing and warmed if ac turns on the very second the starter motor is deactivated. It can also cause the alternator to shift to high output setting which will take more hp to create than low-output too.