Should you turn off your air conditioner before you turn off your car?

Ok here is the reason you turn your AC off prior to turning your car off. Shutting the AC down 2 minutes prior to turning off the car allows the moisture that is in the vents to dry out. This prevents mold from forming in the vent duct work. If you have ever got in to a car and turned on the vent system and smelt the mold, you know what I am talking about. this is due to the moisture that builds up in the vent system. Other then that your AC compressor (If functioning correctly) will only engage once the motor has started. if your AC compressor is engaging prior to the motor starting you have other problems on the AC system. The mold issue is the only reason why you should turn your AC off prior to turning your car off. If you have proper drainage for the AC system this is not necessary.

no its not true and about saving gas with your a/c off its also not true unless you have your windows closed. when you open your windows you are creating an air drag requiing your engine to make more force thus wasting more gas overall you waste the same amount of gas with ac off or on unless your a penny pincher you might save 1 cent on the gallon ??? thats a whole diffrent subject.

I think it would depend a little on just how hot a climate you live in, but generally the engine will run a little hotter as the air conditioner operates. Air conditioners use a system of heat exchanging coils, and the coil that dissipates the heat is usually directly in front of your car's radiator.

If the air conditioner is operating that coil will be hotter and some of that heat will transfer to your radiator. It probably won't overheat your engine, but it will tend to make it cool a little more slowly.

Also, if that system is set to turn on when you start your car you will add to the load on your electrical system as well as increase the work your engine and starter have to do.

If you plan to keep the vehicle for a long time it's generally best to go a little easy on the systems that make it work. Leaving the AC on probably won't damage the vehicle but it may make it wear out more quickly.

No it's not necessary,once you turn that key off everything shuts down,the compressor is driven by the drive belt,once you turn your key the clutch on the compressor will disengage.When you start the car, the compressor is still not engaged to the clutch,once it is running the clutch will engage,and bring the pressure back up.

it all depends if your Flux capacitor is up to date......

gearnofear=, i couldnt have said it better myself you deserve the ten points all other answers have one thing that makes them wrong, that is the correct answer

As a matter of fact you definitely do need to turn it off before you turn off the ignition. Reason?, when your A/C is operating the Compressor is operating, if you turn off your car with the a/c on your compressor is not allowed to depressurize, in other words when u turn the a/c off with the car still on it gives the compressor a chance to wind down before the belt that runs it stops, though the compressor is clutch driven it is good practice to take an extra second or two to turn it off before turning off the ignition. Now if you don't continuously and if your car is new it will be some time but your compressor will crap out on you and will cost you to have it replaced, imagine being in Arizona 150 degree heat, in traffic and the a/c shits the bed, i bet you would rather that not happen, (just an example)

If you care for your car you would turn the air conditioner off before shutting the car off. When returning to your car to start it again the compressor for the air conditioner loads the motor of my car more making it work harder to cool it down. Turn off the AC 5 minutes before you reach your destination and don't keep it working until the last second. If you are not careful you will be replacing your compressor sooner than later. Just think... Do you shut your monitor off before shutting off your computer?

And if any one does i would also like to know....And Why??....................Now ive read the answers theres only one standing on my screen.....and the winner is autotechgenius......When starting the car with A/C on it puts no pressure on your motor what so ever.As the only thing that normally works is any lights you have on and your starter motor when you start your car...think about it!!...Ya radio dont work or the blower fan,only the very basicsat point of ignition untill the key comes back to run......Therefore no power to the a/c.....As for moister in your ducts,thats what the dryer unit is for,to remove any moister in the air...Yes you can get it when using the demister,but only on the window....The A/c will decompress by it self any way,it doesnt need any special help....So NO there is no reason for the a/c to switched off before switchin off the car