Question on E36 radiator fan always on

[tobyo123]

Hi all,

I've noticed that my 1996 318i radiator fan is always on. I'd not spotted this in California where it was always warm, but moving to cold Utah the temperature gauge is permanently in the blue zone to the left and the engine is never getting a chance to warm up.

Question - is there a component that typically fails to cause this?

In addition the heater/AC control on the dash board stopped working ages ago and I never tried to fix it - just opened the window instead. Are the two related or is the cooling fan independant of the Heater/AC systems?

Thanks! Toby.

[XBMWTECH]

Sounds you may have to try to fix your A/C heater control panel first see if the Aux. Fan will stay on? If you know someone have the same year model car with the same Heater A/C control panel the would be a easy test just swap it and see if that fix it.

[tobyo123]

Here's a rather sorry update to this one:

Thanks to XBMWTECH I got busy with the climate control and fixed it - turned out to be a blown capacitor on the circuit board and on replacing it everything started working again.

The fan was still on so I went to Autozone for a new switch. However I then noticed that the car was dumping coolant from the back of the engine compartment and watching the temperature gauge it went cold then climbed steadily and by the time I'd done the last 1/2 mile home the engine was starting to misfire and puff white smoke out of the exhaust..

My theory is that some valve or hose in the heating system didn't take to being put back into service after a couple of years and has failed causing the leak. I can't see at this time where the leak is coming from but there's plenty of it. I'm then thinking in turn that this has made the cylinder head gasket fail hence the smoke.

Questions before I start ripping into the bulkhead; are there any common parts that would fail in the system? It's very hard to see what's happening behind the engine. All I see so far are three hoses going into the bulkhead to the top right of the engine compartment and these don't show any signs of leakage so I'm guessing it's something behind there. I'm crossing my fingers that it's a straightforward leak and then I can dump a can of stop-leak into the system to at least nurse it along while I look at doing a proper head gasket replacement.

I still have the replacement switch to fit in the radiator but this has suddenly become a low priority..

Thoughts anyone?

Thanks! Toby.

[XBMWTECH]

Originally Posted by tobyo123

Here's a rather sorry update to this one:

Thanks to XBMWTECH I got busy with the climate control and fixed it - turned out to be a blown capacitor on the circuit board and on replacing it everything started working again.

The fan was still on so I went to Autozone for a new switch. However I then noticed that the car was dumping coolant from the back of the engine compartment and watching the temperature gauge it went cold then climbed steadily and by the time I'd done the last 1/2 mile home the engine was starting to misfire and puff white smoke out of the exhaust..

My theory is that some valve or hose in the heating system didn't take to being put back into service after a couple of years and has failed causing the leak. I can't see at this time where the leak is coming from but there's plenty of it. I'm then thinking in turn that this has made the cylinder head gasket fail hence the smoke.

Questions before I start ripping into the bulkhead; are there any common parts that would fail in the system? It's very hard to see what's happening behind the engine. All I see so far are three hoses going into the bulkhead to the top right of the engine compartment and these don't show any signs of leakage so I'm guessing it's something behind there. I'm crossing my fingers that it's a straightforward leak and then I can dump a can of stop-leak into the system to at least nurse it along while I look at doing a proper head gasket replacement.

I still have the replacement switch to fit in the radiator but this has suddenly become a low priority..

Thoughts anyone?

Thanks! Toby.

If you want to find that coolant leaks from between firewall and rear of the engine. Best to do is Pressure test system with pressure tester add water to radiator. Pressurize system. Using a good flash light and telescoping small mirror so you can see whats behind that engine. Between rear of the engine and firewall is heater hoses. There is a small coolant hose like a 5/8 fuel line size located above the Starter that hose leaks commonly.