Dumb question about A/C =)

[Phunkatek]

quick dumb question about the A/C in E30's, or all cars for that matter - my friend told me that when you turn on the hot air, with the way that the a/c works in his 325is, what you're actually getting is hot air from the engine. Is that true? I never knew thats how the a/c works...

[MaDhAtTeR]

how can you get hot air from the engine? push some in from the exhaust does it?

[EVOIIIM3]

Hot air with AC? Isn't AC to CHILL the air?

Now a heater works off of coolant water going threw a radiator in the cabin, the temp knob controls the flow.

the AC is basically a small refrigerator.

Air cooled cars, have "heat exchangers" that take he hot air in chambers around the exhaust.

[Phunkatek]

whoops- yeah sorry about that. Yeah the word to use would be when you turn on the heater I guess. Basically when you want some hot freakin air to warm your ass up. Main point just being where the hot air comes from. I guess I always figured the car drew in air and then heated or chilled it accordingly. So it takes hot air from around the exhaust eh?

[EVOIIIM3]

Originally posted by Phunkatek
whoops- yeah sorry about that. Yeah the word to use would be when you turn on the heater I guess. Basically when you want some hot freakin air to warm your ass up. Main point just being where the hot air comes from. I guess I always figured the car drew in air and then heated or chilled it accordingly. So it takes hot air from around the exhaust eh?

NO!!!!!!!!!
AIRCOOLED CARS!, like VW's Big and Porches, use the exhaust

BMW's use the cars coolant, going threw a valve to the cabin, then the fan pushes the air over the hot radiator creating heat.

If you are going to ask questions, think about what you want help with first, then try to call things by their correct names, it really helps if we know what you are asking about.

[MaDhAtTeR]

The AC clutch will cut out aswell. The AC system is seperate from the heating side of things.

[Darien28]

are you sure the AC clutch disengages? cuz mine doesn't. I sometimes put the dial in the middle somewhere if i didn't want the air to be that cold...

also, technically speaking... a/c stands for air conditioning... and i guess conditioning can mean cooling or heating... but that's beside the point...

andyways, as for the heater, the air intake is the same as the a/c air intake... right where the wiper blades are. after the air is sucked in by the blower, it either goes through the A/C evaporator or the heater core or both... the red/blue dial controls the flap which directs air to the 2 chambers. the how coolant flows through the heater core and the air is heated by the heater core. this is why u don't get hot air until your car is warmed up. on the cold setting, the air goes through the a/c evaporator which looks like a small fat radiator that has freon/refrigerant flowing inside of it... if the a/c compressor is on, the air will be cooled, if the ac comp is off, then the evaporator is just sitting there at ambient temp, and the air is roughly the same as the outside air temp.

where the hell did your friend get the idea that hot air came from the engine compartment?? if that was the case, wouldn't the air become cold once you started moving due to the airflow over the engine.... >.>

[MaDhAtTeR]

If you switch it to heat it will, the compressor wont continue to drive while it's being heated. I cant remember if it is thermoswitch controlled or not. The newer cars with climate control will cut in and out to meet the temperature automatically (sensor controlled). If it's set to 20 degrees and the A/C has been on, it will cut out to adjust the temperature.

[Phunkatek]

Alright guys sorry for all the trouble, but thanks a lot.