Question about A/C operation in the winter time

[ez at nova]

I've noticed recently in my 2002 WRX that when I press the A/C button, the compressor sometimes does not come on at all. Other times it comes on, but only for about 10 seconds, then shuts off. I thought this was an issue so I took it to a shop this morning. They just called saying this is normal operation and that the compressor shuts off when it hits its intended pressure. I appreciate them not ripping me off and making unnecessary repairs, but it seems that something is wrong if the compressor doesn't even kick on at all sometimes. I remember in past winters using A/C on "hot" quite a bit to help de-fog the interior windows, so they don't steam up. This doesn't seem right that I can't have the A/C running now. Thoughts?

 

[tjthorson]

If the weather is cold enough, the compressor will not come on. That is because the ambient temp keeps the cold side pressurized enough.

By default most cars have the "defogger" turn on the compressor. Many think it is because it helps defrost the windows. Not exactly true in that the outside humidity is so low in the winter and you dont exactly have a humidifier in the car. It CAN help with window fog in spring and fall.

The bigger reason is just to avoid compressor lockup from sitting all winter and not moving. Keeps the oil moving around and the compressor bearings freed up.

Your car is fine. Dont worry about it.

Spend your time worrying about getting off those RE92's though. I love my WRX, I HATE those tires.....

 

[ez at nova]

Thanks man. The other thing that made me think there may be a problem is that in my garage it's usually never below 40 - 45 degrees, so I figured I could get the A/C to stay on for longer. But, I guess it's not necessarily any more humid in there. I'm tempted to fire up the GN from it's 2 month sleep so far and see how that A/C functions.

(And as far as the RE92's, I only put them on for winter, and they are great for parking lot fun in the snow. They do stink for grip, but it's all about throttle modulation and countersteering!)

 

[tjthorson]

Well, you can't compare too much among manufacturers. Plus, I'm guessing your GN is still R-12, and your WRX is R-134a?

At the very least, even if you converted the GN, it still has an R-12 compressor.

The only accurate way to check is with gauges. That will give you an indication of how the system is working and how much air is in it.... (Air = bad)

Good luck!

 

[ez at nova]

Thanks, and good points. From the help I've been getting from the Subaru guys, apparently our systems are very sensitive and fidgety (i.e. it takes very little for the system to "compress" and kick off in the winter).
I had it checked with guages yesterday and both high and low pressure lines checked out fine. At least the place I took it was honest and didn't ream me. $30 for the time they took with it.