Author Topic: Heating/engine cooling problems (Read 5389 times)

monty23psk · « **Reply #15 on:** October 01, 2009, 10:52:20 AM »

No it does not. You should be able to do it with the key in the igntion and not turned on. Just needs electricity and the temp knob sending the right signal. On my e28, I had both bad. When the knob started to go to hot, it would send 12v to the valve. And depending on the temp setting the signal would oscillate on timer of sorts.

91 318is · « **Reply #16 on:** October 03, 2009, 05:05:35 PM »

Quote from: monty23psk;79248

No it does not. You should be able to do it with the key in the igntion and not turned on. Just needs electricity and the temp knob sending the right signal. On my e28, I had both bad. When the knob started to go to hot, it would send 12v to the valve. And depending on the temp setting the signal would oscillate on timer of sorts.

Well I went out today to see if the valve is working, didn't hear any click. Had the key on, engine off and the fan blowing on low. I slowly rolled the temp from cold to hot, never heard a click. Monday when I go back to work, i'm gonna get my multimeter and see if I'm getting power to it. I'm assuming that the heater valve gets it's power from the temperature control? So if I don't have power to the valve, the temp control switch is bad?

monty23psk · « **Reply #17 on:** October 03, 2009, 05:36:37 PM »

I havent troubshooted the e30 version, but on the e28, it was a magnetic valve. Had 2 leads, one always 12v and the other was dependent on the switch. I would study the ETMs to see how it wired, but your basic theory in my opinion is bad. Also when you turn the knob to heat, the flaps should also turn inside the dash above the heater core. I know on my if I have the blower on and spin the knob to heat and back, I get crap, like old foam debris out the vents. This tells me that the vents are working which might say the knob is ok. On the e28, my knob was bad and you could test by resistance coming out of the knob.

Hope that helps out and good luck.

91 318is · « **Reply #18 on:** October 03, 2009, 07:39:50 PM »

I can hear the door moving, and the heat does work, just not that good, and the engine temp drops. I guess I'll just replace the heater valve when I do the thermostat since you have to drain the coolant for both anyways.

I will be a week or so before I order it, so hopefully I'll reply with good news later