ACZ

Our local Lexus dealer recommended to my wife to always run the heater/ac in the Air Conditioner mode. I did not see that suggestion in the RX manual. Has anyone else received that advice from their local Lexus dealer, and if so, what is the reasoning. It would certainly shorten the life of the compressor.
Thanks - Adam

salimshah

The compressor cycles in and out based on the thermostat and defog settings.

The smarts to disable are built in HVAC system.

You can keep it off ... no harm ... other than cycling it on for 5 minutes every week in winter time too ... the refrigerant has lube for seals.

Salim

Lil4X

Lexus suggests the use of the "Auto" position on the climate control to use the AC coil as a dehumidifier even in the coldest weather. It seems counter-intuitive, but it delivers warm, dry air to the cabin and especially to the defrosters to help keep the windshield and side windows clear in slushy weather. As Salim notes, the system is smart enough to use just enough cooling function to wring water out of the air and circulate lubricant through the compressor as needed.

Even though the Texas Tropics don't get as cold as you folks "up nawth", I've noticed it's a good idea to shut the system "Off" until the engine is warm to prevent light puffs of chilly air propelled by the HVAC blower from raising the misery index. After less than a mile you can poke that "Auto" button and begin to enjoy warm air. On cold mornings I routinely turn the seat heat up to "broil", and the fan speed to full max - just to hasten the thawing process.

ACZ

Thanks for the tips.

Doesn't having run the a/c reduce gas mileage and if so how much?

Yes it can be cold up here in Dayton, Ohio. I use the "butt" warmers all the time. My wife has a 01 and I just got the 00. Hers has a low or high, where as mine has high. It is like a heating pad and can get too hot. In the mornings it is a nice feature.

I really enjoy reading these threads as I am kind of new here.

salimshah

The only time A/C robs power would be when compressor is running (assume inside blower is low energy hog).

A while back there was a discussion on mpg. There are too many variables like temp inside the cabin, temp outside, speed of the RX etc etc. The simplest recommendation is to roll up the windows and have the AC on, will get you the most milage.


Salim

Lexmex

Using A/C on the 1/4 mile track can blow 10 hp, we had a few guys on a dyno simulate there launch and the number of seconds they would normally run with and without the a/c.

Ymmot

Not so long time ago i saw a test where they take same car fill it up run it with ac and windows up on a track untill empty ...next they did was filliing up again ac off and windows down ...it ran a much longer distance with that constellation compare the ac ride ..so the knowledge about ac windows up give u more miles is not correct ...why the car producers claim it more effecient i dunno besides selling more parts ...i actually think the test was done by mythbustersnailing that one clearly as i remember..it also corrspond with the 10 hp loss lexmex is talking about

Bill Dowd

you don't have to always leave it on but like the man said above, turn on your A/C weekly to lube the seals my 1986 toyota cressida went 529,000 on the same compressor and my 2000 ls400 now has 237,000 miles on the same compressor I turn it on weekly in the winter and run it like hell in the summer in So Cal

code58

If you are using your defrosters in the winter, you are using your compressor. They have been wired that way from the factory since before some of you were born. The seals get lubed that way without you remembering to run the A/C and since is a drier, it tends to defrost until the heat comes up. And defrost doesn't necessarily have to use heat. Moving air will do also, though obviously not as quick as heat. I'm old enough to remember but some of you may not be aware, the cars say in the 20's sometimes had a little auxiliary fan mounted up on the side by the windshield (no heater), and you had a switch that you could turn on to blow air on the W/S to defrost. Air movement is what it takes.

P.S. your compressors went the long haul because Denso (which I'm betting they were/are) makes good goods!