On the way home today I heard the fan start up and it stayed on and never shut off. 2018 F60 All4 JCW. Temperature outside was -13C (9F), warmest day in about a month! There was little to no heat coming from the vents, which were working fine earlier. Turned on the temp gauge on the dash…it showed neither OK or COLD, which is unusual. No warnings until I got home, just the Notification that warned the engine compartment could be hot when opening the hood. Wrong…I opened the hood and the engine compartment was cool…I could put my hand on the block…but car had been running for probably 2 hours and making heat earlier, fan running full bore must have cooled everything off?
Just got in the door, haven’t checked for codes yet, or fuses or anything. I did a quick search here but didn’t find anything right away.
Any ideas? Maybe a coolant temperature sensor? Is there a fan switch? I will check for low coolant level and fuses but I don’t suspect they are the issue…going to check codes now….
Looking for ideas or if anyone has had a similar issue…? Thanks in advance.

 

I went to check codes, has P0128 - Coolant temperature below thermostat regulating temperature. I cleared the code and started the car. I put my scanner on Live Data and found ECT which I assume is EngineCoolantTemp? I watched this slowly go up. Gauge on dash showed ‘COLD’ until temperature reached 140F where the gauge turned to ‘OK’. I continued to watch it climb to 160,180 and up. I had to stop monitoring but it had climbed to 200 and even 220F and the fan did not come on. Anyone know at what coolant temperature sensor the fan kicks in? (Update…looks like B48 run hot, 217-237F….should have taken it higher…and longer)
I was thinking the fan should have kicked in by now. I shut off the car, the fan did not come on.
Will do some reading…I don’t know where any of the sensors are or maybe there is a relay….stay tuned…
Oh, forgot to mention….heat was now coming from the heat registers normally while the engine was running!?? Temperature sensor seems to be working…thermostat is working…

 

Dropped my daughter off at work this morning, similar outside temp, and I monitored the coolant temperature. It seemed to top out at 223-225 and couldn’t get it higher in the hour I was driving around, even a stint using no interior heat. I held lower gears to increase heat production but that didn’t have significant impact on temps. The fan never came on. Thermostat seems to be keeping the engine at the correct temp, around 103C/217F.
Parts diagrams show an ‘oil coolant temperature sensor’ (13627580635) on the block and a ‘coolant temp sensor’ or ‘fan switch’ in the area of the radiator (13621433077) not sure of location of the latter as the diagrams have it floating in space. Seems to be somewhere on the passenger side, but not sure if radiator mounted or ? Checked on ECS and doesn’t show this part as fitting F60, so am a bit confused.
I’m leaning towards the sensor in the area of the radiator, if there is one, possibly not working correctly as the fan came on yesterday but didn’t turn off when it should have. The fact that I can monitor coolant temperature tells me the block sensor should be working correctly.
I will go for a drive later and try to duplicate what happened yesterday, and hopefully get coolant temps above 225. Currently, everything seems normal. I have to assume there is still coolant in the radiator that hasn’t come to temperature yet?
Assistance in locating that sensor in the area of the radiator ( if there is one) or other sensor I may have missed would be appreciated. Some BMW seem to have the sensor on a lower rad hose, but not so with F60. Not finding much on the net.

 

Hmmmm…just back from a 2.5 hour drive, everything normal, operating temperatures of the motor were in the normal range, interior heat working normally. No codes. Radiator fan never came on.
I am still unsure what controls the radiator fan…is there a sensor, is it controlled by the ECU, or ??
I guess I will monitor and see if what happened yesterday…rad fan started but would not shut off, eventually robbing all the heat from the motor….will happen again.

 

Looks like no one has responded to you…

The fan is controlled by the ECU with input from the ECT sensor and thermostat. Maybe the thermostat got stuck that day? I remember in my 2012 Clubman when the thermostat failed the fan ran full bore after shutting off the engine. Maybe your thermostat is not quite failed, but on its way out?

 

Thanks for responding Nik. I am currently thinking similar that it was a bit of a glitch, and will continue to monitor. The weather had warmed up a bit after over a month continuously in the -30C/-22F range, so maybe things were operating a bit differently that hadn’t happened in a while.
I will continue to monitor and collect the possible parts I may need some day. The sensor you mention is in the block, or elsewhere?
Thanks.

 

On the B46/48 engines, the engine coolant temp sensor is under the intake manifold in the block. The manifold has to be removed to access the sensor.

The water pump and thermostat are located on the front of the engine, on the drive belt side.

 

Update….the rad fan that wouldn’t turn off appears to have been a one-off issue thus far. I will update if that changes.
Thank you Nik for responding…I’m always willing to learn more about my F60 and you have been helpful this time and previous!

 

No problem. Hopefully it was just a fluke day. Just keep driving!