[dinozoros]

My 328i just started to overheat in this summer heat and we cannot seem to find any problems with the cooling system ALTHOUGH there is no auxiliary fan sensor box mounted on the shroud and I can't remember if there ever was one. Can't even find a cable to run to the box either if there was one at any point, and this would explain the overheating if these sensors are supposed to be there.

Thanks, Dino

Ps part number for the aux fan sensor is 64118391470

 

[BartenderPlease]

If your fan is plugged in, that should be enough. I think the coolant temp determines when that kicks in.

I'd be willing to bet it cools down once you start moving?

 

[dinozoros]

Yes of course it does, it's only when I'm idle say in traffic or so

 

[dinozoros]

If your fan is plugged in, that should be enough. I think the coolant temp determines when that kicks in.

I'd be willing to bet it cools down once you start moving?

I never get the chance to test it though because I've turned the car off as soon as it rises past operating temp

 

[BartenderPlease]

So if you have a mechanical fan you may need to replace the fan clutch. Or just convert it to an electric puller fan.

 

[dinozoros]

So if you have a mechanical fan you may need to replace the fan clutch. Or just convert it to an electric puller fan.

I still dont know if there is supposed to be that aux fan sensor box ontop of the fan shroud though?

 

[turbo1168]

Look for the user named BMW-north, he has a section on cooling fans on his page. Early models had the final stage mounted on the end of the motor, not a separate box if I understand correctly.

Sent from my 5049W using E46Fanatics mobile app

 

[BMW-North]

Sure has the symptoms of a failed fan or lower coolant temp sensor (CTS). Read the sections on diagnosis. You really ought to add the year of your car and tranny version so folk can help.

BMW-North E46 Electric Fan Guide

Edit: that little box on top of the fan shroud is an air quality monitor. It has nothing to do with fan operation.

 

[dmax]

It could also be your therm isn't opening all the way. If you haven't replaced it in some years, I'd do that along with the WP and get some fresh coolant in there. Give it a good rinse with distilled water too in case there's gunk built up. I'll fill mine with water first and make sure the work I did holds water before draining and filling with 50/50 mix.

 

[74123]

Replace the thermostat

Cheap enough and a rel easy diy.