To run or not to run the A/C?

LouDawg · Apr 19, 2007

How often should I run the A/C compressor? I always go back and forth between running it (keeping it lubed from what I've read) and not running it to save gas. My Honda has the auto climate system, and from what I've heard, if you have it on Auto, it will always run the compressor. I don't want that, but I don't want to have to manually turn it on/off all the time, either.

So any ideas on how often, at minimum, it needs to be run to maintain lubrication? Or should I just set it on Auto and forget it?

TIA

Quest · Apr 19, 2007

For R-134a systems running PAG oil or similar, I typically run my A/C all year long once every week to 10 days, for approx. 10~15mins, rain or shine. This is to properly lubricate all the internal mechanical components to minimise seizure.

alreadygone · Apr 19, 2007

Moove farther south, won't be a question in the summer.

Bob

rpn453 · Apr 19, 2007

A/C systems don't see much use for long periods of time during the winter up here, and they're not a frequent maintenance issue. I think once a month should be plenty.

ThirdeYe · Apr 19, 2007

In my car's manual it says to run the A/C at least once a week to keep it in tip-top shape

EDIT: D'oh, Quest beat me to it

mstrjon32 · Apr 19, 2007

If you're just cruising down the highway, you'll actually break even on running the A/C and having the windows open. You may actually save gas with the A/C.

I don't think this would be the case with constant start/stop city driving, however.

tom slick · Apr 19, 2007

if you use your defogger during the winter then you are cycling your AC system.

Doc8404 · Apr 19, 2007

Quote:

if you use your defogger during the winter then you are cycling your AC system.

depends on the vehicle....my Galant has to be turned on manually.

LouDawg · Apr 19, 2007

I'm told on an Accord forum that if you run the HVAC system on full-auto, the compressor runs constantly. I don't want to do that, but I'd like to use full auto just for convenience, or laziness.

If it cycles on and off as needed, I'm cool with that (pun intended).

southernjeeper · Apr 20, 2007

Quote:

Moove farther south, won't be a question in the summer.

Bob

YEP down here u will definitely need it!!!!!!!!!!!!

i don't see how people live without A/C in their cars...

sprintman · Apr 20, 2007

Wekly to keep seals etc lubed

Merkava_4 · Apr 20, 2007

Quote:

I don't want to have to manually turn it on/off all the time, either.

Can you still turn it on or off manually if you wanted to? Myself, I don't like automatic climate control and glad I don't have it; it just adds more complexity to a car that I find unnecessary, like heated seats for example. I just turn mine to full cold and adjust the fan speed as needed; I don't find it any trouble at all. If I don't have the A/C on, I'll be running the fan that pulls the outside air in. I rarely have the windows down; my GM car has weak window regulators, so I try not to use them at all unless it's absolutely necessary.

rpn453 · Apr 20, 2007

It seems I may have been subconsciously influenced by my Pathfinder's owner's manual. I know I had read this before, but forgot about it on my previous post. The Pathfinder's compressor never turns on automatically, and the manual says:

"The air conditioning system should be operated for about ten minutes at least once a month. This helps prevent damage to the system due to lack of lubrication."

LouDawg · Apr 20, 2007

Quote:

Quote:

I don't want to have to manually turn it on/off all the time, either.

Click to expand...

Can you still turn it on or off manually if you wanted to? Myself, I don't like automatic climate control and glad I don't have it; it just adds more complexity to a car that I find unnecessary, like heated seats for example. I just turn mine to full cold and adjust the fan speed as needed; I don't find it any trouble at all. If I don't have the A/C on, I'll be running the fan that pulls the outside air in. I rarely have the windows down; my GM car has weak window regulators, so I try not to use them at all unless it's absolutely necessary.

Yes, it can be turned off manually. If I hit the A/C button from Full Auto, it displays "A/C Off".

Drew · Apr 20, 2007

During winter months I run my A/C when taking an offramp off the interstate and when driving down hill on the highway. I do this every several days and haven't noticed any decrease in my average 43mpg winter fuel economy. In summer wx, I shut off my a/c when going up hill or accelerating and run it on low setting only on flat stretches of road and still manage to get 46mpg in the summer

brianl703 · Apr 21, 2007

Quote:

I'm told on an Accord forum that if you run the HVAC system on full-auto, the compressor runs constantly.

IF it is a variable-displacement compressor that is most likely true but only IF the controls determine that the compressor is really needed. On my Saab 93 the ac compressor will not come on if I increase the set temperature above the current cabin temperature--there would be no point to that.

johnd · Apr 21, 2007

Around here in the winter you only run the ac in the afternoons so it isn't much of an issue. That being said, I certainly wouldn't go over a month without turning it on.

Axe Man · Apr 21, 2007

Quote:

It seems I may have been subconsciously influenced by my Pathfinder's owner's manual. I know I had read this before, but forgot about it on my previous post. The Pathfinder's compressor never turns on automatically, and the manual says:

"The air conditioning system should be operated for about ten minutes at least once a month. This helps prevent damage to the system due to lack of lubrication."

If your vehicle's owner's manual doesn't have this statement it's a safe bet that the HVAC system cycles the compressor in defrost mode, regardless of whether you have automatic climate control or not. Most newer vehicles operate in this fashion and it's easy to find out:

Open the hood with engine idling.

Have a helper turn the controls to defrost and fan on.

Watch/listen to the compressor clutch.

If it clicks and engages the compressor cycles automatically in defrost mode which would negate running the A/C manually in winter unless you never use defrost mode.

If your vehicle has a separate condenser cooling fan you may even be rewarded with that fan cycling on/off or staying on. That's also another indication that the compressor cycles in defrost.

Even my low buck Civic VP operates in this fashion. It serves two important functions. It keeps the seals lubricated plus the compressor helps to dehumidify the cabin.

AcuraTech · Apr 21, 2007

Quote:

I'm told on an Accord forum that if you run the HVAC system on full-auto, the compressor runs constantly.

No. The compressor cycles on and off. So do the fans.

Merkava_4 · Apr 21, 2007

Quote:

Quote:

I'm told on an Accord forum that if you run the HVAC system on full-auto, the compressor runs constantly.

Click to expand...

No. The compressor cycles on and off. So do the fans.

Well there you go LouDawg, now you don't have to worry about wearing your compressor out; just set it and forget it.

To run or not to run the A/C?

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