Does your AC cycle on/off ?

[GT Wagon]

Mine does, regardless of what setting I have it on (vent, floor, combo....) you can feel the AC motor cycle on/off as I'm driving. This is my first Subaru with AC, my other cars never did this. Our 00 Forester doesn't do this either. I'm wondering if its something the '97's did or if there's a problem.

[Manarius]

The AC cycles on and off on the 97 my friend has....when the AC selector is on. I would think it's a fuel saving device. Why run the compressor all the time, when you don't need to?

When I turn on the AC in my 91, the compressor stays on constantly.

[ivwarrior]

Essentially all vehicles do this, it's just more noticeable in some than in others. It's at least partially to keep the evaporator core from freezing up. The "off" period allows it to warm enough that the moisture from the air can melt off and drip out the drain. Yes, the A/C really is that cold, stick a thermometer in the vents and check vent temp. Evaporator temp is going to be lower than vent temp.

[Plays_with_Toys]

Mine does it too. If you do a grounding kit the hit from it switching on/off isn't as bad.

[GT Wagon]

Good to know ! Seeing as I just dropped $1400 fixing the motor I wanted to make sure this wasn't another problem about to strike. Also, having another Subaru that does not exhibit this behavior made me warry.

My former cars, Toyota's, Mazda, VW's.... never exhibited such a noticeable cycle past the intial turn-on.

[Christopher Marks]

I notice it on both my 99 Legacy and my brother's 02 Outback. I think it's a little smoother on the 02 though.

[ooberdoob]

it's not a gas saving thing, the system has a specific rage of pressure to run in, when it gets to the upper limit, the pressure sitch kicks it off and vice versa.

it's so it doesn't blow the hell up. in simple terms.

[Wiscon_Mark]

Some cars (mostly older GM cars) would run the heater w/ the A/C instead of cycling the A/C on and off. But that would use more energy/be more stressful, etc.

[ooberdoob]

what the hell are you talking about mark

[Wiscon_Mark]

Some older A/C units run the heater w/ the A/C to keep the temperature steady instead of cycling it on and off. That system probably isn't used anymore, as it's less efficient.

[legacy4ever]

well, my AC doesn't cycle at all :-(
is there something wrong? actually it's swapped from a '91 Legacy. maybe some wiring problems? faulty thermo sensor? It blows ice cold though. runs still on R12...

[losdiosdeverde86]

they're also supposed to shut off if the TB is past a certain % open. you can really tell on my car because the AC clutch chirps everytime the AC compressor kicks on.

there's also a noticeable power drain/thrust when it's on/off (respecively)

[ooberdoob]

my ac compressor eats power.

makes me want a V8 :-(

[losdiosdeverde86]

my ac compressor eats power.

makes me want a V8 :-(

yeah. sometimes i have to turn off the ac to keep my speed up going up a hill.

[ooberdoob]

i have to hit the switch all the time! :lol: also cause i have a 5MT and when the AC is on it changes how the car shifts completely.

(for those who've never experienced it) the revs drop faster and the engine is slightly less powered, so you either have to burn the clutch more or, like i do, wait just a split second to let of the gas when i shift and it usually matches right.

[Wiscon_Mark]

yeah, it causes humungus hesitation around town...but I don't use it around town unless the heat is just unbearable.

[Manarius]

well, my AC doesn't cycle at all :-(
is there something wrong? actually it's swapped from a '91 Legacy. maybe some wiring problems? faulty thermo sensor? It blows ice cold though. runs still on R12...Nope. My 91's runs all the time.