E36 overheating

[///Motorsport KoP]

Hello fellow bee em koppe,

i have a slight issue. My car overheats sometimes, so far once every 2 weeks i'd say when in traffic or standing still for long.

I did a test, Last night i let the car idle and for about 10 minutes it was fine - fan switched on 3 or 4 times, then suddenly it doesn't switch on and the car over heats. Im assuming the Thermo Sensor/Thermostat is working intermittently?

 

[Kyle]

Put the heater on full once the car is heated up, good way to test your thermostat :thumbs:

 

[Peejay]

It's the vicious fan. Think you need a new 1.

 

[///Motorsport KoP]

@KyleNaidoo - what am i supposed to look out for? I did actually do this while the car was idling, all i could gather is it takes longer for the car to heat up and for the fan to switch on...

@Heven - Can't be the fan, it DOES go on....

 

[Peejay]

The viscous fan or fan clutch in behind your radiator. When the car is hot you should be able to turn it. If it turns freely it's time to change. It's there's some resistance then it's probably the thermostat.

 

[Kyle]

His fan is electric..

Does the heater blow hot air when the car is up to temp? If not, your thermostat could be faulty. If the heater works fine then check the sensor.

Had the same problem on my car, turned out to be a faulty thermostat

 

[Peejay]

The fan you speak of is the aux fan. And that's in front on the radiator. I'm sure you can see it through the grill.

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Ah.

I'm sorry. Most probably thermostat then.

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You can feel the radiator pipes. One should be hot while the other warm.

 

[Gizmo]

The fan not coming on is probably the low speed fan relay being intermittent.

 

[ters]

Hello fellow bee em koppe,

i have a slight issue. My car overheats sometimes, so far once every 2 weeks i'd say when in traffic or standing still for long.

I did a test, Last night i let the car idle and for about 10 minutes it was fine - fan switched on 3 or 4 times, then suddenly it doesn't switch on and the car over heats. Im assuming the Thermo Sensor/Thermostat is working intermittently?

Maybe I misunderstood some of the terminology other posters use...:=): It sounds as if your Thermo fan switch on the radiator is working intermittently. This switch activates the auxiliary fan/s once a certain temp. is reached. They are available in different heat ranges, an inexpensive fix.

Ters.

 

[///Motorsport KoP]

Thanks guys! i too think it is the Thermo Fan Switch.

@Heven - i aint messing with the fan when the car is hot, it could switch on an slice my fingers! I'll check the pipes like you say, 1 HOT and 1 warm..

@KyleNaidoo - NO - i had teh car idling and it was up to temp but the heater was on full blast but no hot hot air, just bearable warm air.

@Gizmo - which relay is that, will the car manual point this out to me?

and thanks @ters i think so too, just always need more informed BMW owners opinions :thumbs:

 

[Peejay]

The vicious fan is mechanical, won't come on if engine is off.

But that wouldn't matter now as I think you deleted it.

 

[Kyle]

Well if the air is warm then its the sensor or relay as gizmo said :thumbs:


Sent from the Death Star

 

[Gizmo]

Guys you are missing the fact that the e36 318is doesn't have a viscous fan, only an electric one between the radiator and engine. The 318is has a 80/88 degree thermostat switch which in turn grounds the fan relay and power is sent to the fan. In all my years of working on E36's I have never seen a themostat switch go faulty, my money is on the low speed fan relay which do go faulty.

This should help.

 

[Peejay]

Thanks gizmo. :thumbs:


Had no idea that the 318is has no viscious

 

[///Motorsport KoP]

Gizmo for the next president :thumbs:

I'll replace the relay ASAP and will get back to you guys with an update!

Appreciate all the help :=):

 

[///Motorsport KoP]

Hey @Gizmo, it's me again. So i did replace the relay as you said, and this seemed to have fixed the issue as the car stopped overheating - that was until last week and again yesterday! Once the car was cooled down i checked again and the fan DID switch on. I am again now confused what the problem is

Guys you are missing the fact that the e36 318is doesn't have a viscous fan, only an electric one between the radiator and engine. The 318is has a 80/88 degree thermostat switch which in turn grounds the fan relay and power is sent to the fan. In all my years of working on E36's I have never seen a themostat switch go faulty, my money is on the low speed fan relay which do go faulty.

 

[Peejay]

Try re bleeding the system. :thumbs:

 

[///Motorsport KoP]

Try re bleeding the system. :thumbs:

Hey dude
I have but maybe I am doing it wrong? How should I do it. .

 

[Peejay]

I'm not sure on a 318is. This is how I did I'd on my 328

Idle the car. Heater in the car should be on maximum. At the side of the water bottle there should be a bleeding screw that needs to be opened. As the car heats up you'll see bubbles coming through the screw. When there's no bubbles you're good to go.

 

[///Motorsport KoP]

Me again

So i think i have figured out what is wrong. I jumpered the Aux Fan Temp Switch to simulate Low speed and High speed. High speed it turns on but for Low speed it does not. I checked the fuse is fine, replaced the relay too, but still low speed fan does not switch on. What could it be?!?!? Please some help me.....im desperate as this coudl turn into a bigger problem. I just had a issue this morning with overheating again