legacycentral bbs

Alright, so I am trying to get an understanding of how the heating, cooling, and radiator fans work (when they should turn on).

Right now I'm having a cooling problem with my SS. It won't heat up. 12 mile drive into town and I'm lucky if I hit 140 degrees. When i come to a stop, with the heat on (not defrost, not BILEV, not vent) the fans kick on, if i open the hood and hold the throttle open a little they will kick off. And I'm not sure why this is. Any ideas?

My other question is: I know that when I turn my defrost on, my radiator fans come on. Do they stay on when I am driving? Also, I read online that the A/C system (which I don't have in my car) is tied into the defrost system (on some cars) and when the defrost is turned on the A/C compressor engages, is this true for our cars?

I know these seem like simple answers, but I am truly stumped on why my car won't heat up. So anything helps.

First I would suspect the thermostat for the engine not heating up. If you replace it I highly recommend oem Subaru because most aftermarket ones won't open. As for the fans staying on the temp. Sending unit operates the fans, and yes the a/c is activated when the defrost is pushed and fans kick on. But you stated you don't have a/c so I'm not sure the fans should kick on when defrost is pressed.

I'll second replacing the thermostat. That is why the car isn't heating up....and most definitely buy it from Subaru. When I first got my car in 95 I didn't use a Subaru thermostat and had weird engine and overheating temps. Put in a Subaru t-stat and all was good.

So start with that. If you have a lot of miles on the engine, I'd probably also suggest replacing the coolant temp sensor if it hasn't been replaced. The sensor has a lot of bearing on air fuel ratio control, not to mention fan control. It's about $20 from the online subaru dealers.

I would start with those things and see how that affects/changes what you're seeing.

Did your car originally have AC? If so, that's likely why the fans are turning on. With a properly working t-stat, it shouldn't matter whether the fans are running or not.

Damnet Logan you can ask your brother and I these questions, it's not like I was a master tech or we both went to tech school or anything, lol. But to answer your question the A/C fans will cycle on and off with the A/C pump and on our cars the pump runs continuously with the defrost on. So even though you don't have your pump installed the HVAC control doesn't know this and kicks the fan on. Also almost all cars on the road today have the A/C tied into the defrost, one of the main purposes of A/C is to dry the incoming air before it gets sent through the HVAC box, and dry air clears your windshield much better than damp humid air, obviously. This is why it's called air conditioning and not air cooling or whatever. Have you figured out why your fans are coming on in the "Heat" position? I know your on the college student budget but I agree with everyone else in that you should look into replacing the ECU coolant temp sensor if you haven't yet.