Tsmith1982

Hey Guys. I am curious to know if turning off the AC before turning off the car provides any benefit to the AC system itself? For years I have heard it relieves the pressure on the AC Compressor and that it prolongs life. I know some guys do it here to help with mold issue. But I wonder does it provide any other benefit? Have I been hearing a myth?? What do you guys do?

williakz

In my 2007, it was simple. Set temp to desired, punch system AUTO button, punch air intake mode AUTO button. Forget about the HVAC system FOREVER. Now, a new regime is in place, and the definitive mode of operation has not yet been determined either by owners or by Lexus, it appears. Good question - I hope it finds an answer.

RandyV

I got in the habit of turning off the AC about 1/4 mile from my destination when I owned a BMW 7 as this allowed any accumulated moisture in the system to be evaporated rather than sitting and creating a mold-friendly environment. If not done the ventilation system would develop a musty odour.

I had the same issue with my Porsche.

So I continue that practice on the LS for the same reason.

krypto89

i have been doing it for all the cars i've owned for the two reasons you stated. my dad told me to do it when i first started driving. not sure if this is a fact or a myth, but it doesn't hurt to do it. it will come second nature after a short while...

slimjimtel

Definitely Don't want to do this if you have remote start. It would defeat the purpose of cooling the car down.

jud149

Whether you turn it off from the switch or key, the result is the same. Power to the compressor is cut immediately. This goes way back, I think, to when some used to shut everything off before doing so with the ignition. Some used to rev the engine and turn off the ignition during the process thinking it charged the battery. Actually it did the opposite. Just my 2 cents.

Tsmith1982

That's what I'm thinking is that it was a myth of prolonging life of the compressor

jud149

FWIW, my other car is a '91 Lincoln Mark VII that has about 200K miles on it. I live in FL and the compressor runs most of the time. I bought the car new so I know it's the original compressor and I've never shut the a/c down before shutting off the ignition.

sydtoosic

i always forget to turn the damn thing off... been to Lexus twice for the smell, they finally put in a charcoal filter... smell is coming back. damn shame.

williakz

NOT your job to "remember!" Lexus's job to properly engineer an AC system they had PERFECTED in 2007. Agree with "damn shame" entirely...

slimjimtel

If you have a smell in your AC, it's time to do an AC refresh. They shoot a cleaner in the coils and let it drain, then do the spray in the front cowl.

IT WORKS!! You can do it yourself, the kit is like 24.00 or 14.00 from Sewell with your CL discount.

I have done it for years in my cars, I try to do it once a year and sometimes twice. It helps with odors in the car including the little bit of mildew you smell in the mornings. The mildew is from the wet coils in the box behind your glove box.

One trick is to turn AC to fresh air for the last several minutes of you drive, it helps dry out the box before you stop.