Auxiliary fan issues

Mik325tds · 08-27-2014, 04:51 PM

Can you guys do me a favor and measure the coolant temperature at which the auxiliary fan starts kicking in?
Mine rose to 96C today and the fan still didn't run so I switched on the AC which started the fan by default.

I got concerned when I noticed that every now and then the fan kept running after I shut off the car. A quick research on the knowledge hive indicated that this is normal if you turn off your car while it was in the middle of performing a DPF refresh. However, mine kept running for more than 30 min until I thought there might be something wrong. I started the car and turned it off again which took care of the problem.

Strangely enough, the fan responds fine to diagnostics request to the DDE, yet it threw me a code the other day indicating a problem with the fan.

Mik325tds · 08-31-2014, 08:36 AM

Bump. Anyone?

Please do the following test:
Secure your car against rolling away, let the engine idle, AC off, put in gear to increase the load. Open the hood and watch the fan and "engine coolant temp" on the Torque App (or whatever). Please let me know at which temp (>87C) the fan starts running.

Your help is greatly appreciated.

Yozh · 08-31-2014, 06:55 PM

I can run this for you when I come back from the long weekend. But I have never heard the fan come on unless it was for the ac or during a regen. I can look up the temp data as well if I ever hit the 96 before.

Mik325tds · 09-01-2014, 09:30 AM

Thanks Yozh. Looking forward to your results. You might need to watch the fan as the DDE might only give it 10-20% PWM for temps just above 87C. At that speed the fan will probably inaudible.

Yozh · 09-03-2014, 06:39 PM

Sorry I have not ran this yet. Was long weekend then bunch of rain. Should be able to check tonight.

Yozh · 09-04-2014, 09:02 PM

Ok, at idle the fan does not turn on at 96c. When increasing the load the fan will come on (10-20pwm) at about 98c and will run until the temp drops to 95c. Hope this helps.

Mik325tds · 09-05-2014, 03:59 PM

Thanks Yozh!
I feel much better now. It seems 98C is not a problem for the engine as we see those temps during regens, too.
Yet, I'm still a bit baffled why the DDE doesn't start cooling the engine earlier. I confirmed today with 30C outside temps, the fan came on just before hitting 98C.

Good to now that this is normal though. Thanks again!

08-27-2014, 04:51 PM	#1
Mik325tds Major 806 Rep 1,191 Posts Drives: 335d M-Sport Join Date: Jul 2014 Location: Greater Detroit iTrader: (0)	Auxiliary fan issues Can you guys do me a favor and measure the coolant temperature at which the auxiliary fan starts kicking in? Mine rose to 96C today and the fan still didn't run so I switched on the AC which started the fan by default. I got concerned when I noticed that every now and then the fan kept running after I shut off the car. A quick research on the knowledge hive indicated that this is normal if you turn off your car while it was in the middle of performing a DPF refresh. However, mine kept running for more than 30 min until I thought there might be something wrong. I started the car and turned it off again which took care of the problem. Strangely enough, the fan responds fine to diagnostics request to the DDE, yet it threw me a code the other day indicating a problem with the fan.
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08-31-2014, 08:36 AM	#2
Mik325tds Major 806 Rep 1,191 Posts Drives: 335d M-Sport Join Date: Jul 2014 Location: Greater Detroit iTrader: (0)	Bump. Anyone? Please do the following test: Secure your car against rolling away, let the engine idle, AC off, put in gear to increase the load. Open the hood and watch the fan and "engine coolant temp" on the Torque App (or whatever). Please let me know at which temp (>87C) the fan starts running. Your help is greatly appreciated.
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08-31-2014, 06:55 PM	#3
Yozh Colonel 870 Rep 2,615 Posts Drives: 2011 335d M-Sport Join Date: Mar 2014 Location: Wet Coast iTrader: (4)	I can run this for you when I come back from the long weekend. But I have never heard the fan come on unless it was for the ac or during a regen. I can look up the temp data as well if I ever hit the 96 before.
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09-01-2014, 09:30 AM	#4
Mik325tds Major 806 Rep 1,191 Posts Drives: 335d M-Sport Join Date: Jul 2014 Location: Greater Detroit iTrader: (0)	Thanks Yozh. Looking forward to your results. You might need to watch the fan as the DDE might only give it 10-20% PWM for temps just above 87C. At that speed the fan will probably inaudible.
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09-03-2014, 06:39 PM	#5
Yozh Colonel 870 Rep 2,615 Posts Drives: 2011 335d M-Sport Join Date: Mar 2014 Location: Wet Coast iTrader: (4)	Sorry I have not ran this yet. Was long weekend then bunch of rain. Should be able to check tonight.
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09-04-2014, 09:02 PM	#6
Yozh Colonel 870 Rep 2,615 Posts Drives: 2011 335d M-Sport Join Date: Mar 2014 Location: Wet Coast iTrader: (4)	Ok, at idle the fan does not turn on at 96c. When increasing the load the fan will come on (10-20pwm) at about 98c and will run until the temp drops to 95c. Hope this helps.
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09-05-2014, 03:59 PM	#7
Mik325tds Major 806 Rep 1,191 Posts Drives: 335d M-Sport Join Date: Jul 2014 Location: Greater Detroit iTrader: (0)	Thanks Yozh! I feel much better now. It seems 98C is not a problem for the engine as we see those temps during regens, too. Yet, I'm still a bit baffled why the DDE doesn't start cooling the engine earlier. I confirmed today with 30C outside temps, the fan came on just before hitting 98C. Good to now that this is normal though. Thanks again!
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