E39 Aux fan (electric fan)

[BimmerDan]

Just found out that my Aux fan is frequently running on speed 2 which is extremely noisy. At first I thought it was the clutch fan that's failing but it checked out OK, so it could very likely be the Aux fan. However, the Symptoms are :1) Aux fan will be on speed 2 the from a cold start and can last for 2-3 minutes before it cutting off.2) Speed 2 comes on the moment car is running on low speed (under 20kph)3) Aux Fan, speed 2 comes frequently even when driving on a highway.Appreciate it, thanks.

 

[macgy]

what year is your E39?

 

[BimmerDan]

I'm driving a M54 engine 520i

 

[harbhajan]

hai i had the same problem with my 530 i change my temp switch,located at the water hose was ok.can call me 0199868542

 

[hky]

err, may I ask how to know if its on Speed 2 or not?

 

[BimmerDan]

the blade spin is quicker and overall nosier, that is speed 2.

Temp switch?

 

[hky]

mine also like that when car is idling. hmm. will there be any error on the BMW scanner?

 

[BimmerDan]

from what I understand the scanner doesn't detect such fault

 

[hky]

in that case, how do I know if the temp sensor is fault or not.

 

[bmw7833]

Why not give harbhajan a call since he is willing to share his experience with u.

 

[hky]

ok thanks

 

[bimmer73]

Guys

Our Aux fan does not run speed 1, 2 or 3 there is no such thing it is driven by the ECU, when it on full speed it sound like aircraft propeller when it is low speed it like a ceiling fan on No 1 . It could be your tempreture sensor like harbahjan said. The other reason is the AC compressor pressure is too high. I have had this problem before on cold start in the mornings my brand new AUX fan come on automatically on high speed wen it is suppose to come on intermittenly. I cracked my head for 2 months and was told by my mechie (bestness motorsport) that the cause was The AC compressor. After changing compresor at Naidu's the fan was back to normal.

 

[macgy]

bro, how much did u pay to change d compressor? new? brand?

 

[rafamr]

Consider tumpang this thread.

I noticed my electric fan still running after switching off ignition. Do happened several times. It wont stop even after 2 or 3 minutes after switching off. I need to restart and switch off again to stop the fan from continues running. Remember its has been discussed somewhere here. What are the possible symptoms.? Thanks!

 

[tweiboon]

Guys

Our Aux fan does not run speed 1, 2 or 3 there is no such thing it is driven by the ECU, when it on full speed it sound like aircraft propeller when it is low speed it like a ceiling fan on No 1 . It could be your tempreture sensor like harbahjan said. The other reason is the AC compressor pressure is too high. I have had this problem before on cold start in the mornings my brand new AUX fan come on automatically on high speed wen it is suppose to come on intermittenly. I cracked my head for 2 months and was told by my mechie (bestness motorsport) that the cause was The AC compressor. After changing compresor at Naidu's the fan was back to normal.

My fan is driven by the fan belt. Is it my fan got low speed and high speed ? My e39 is 1999 523i. How it works ?

 

[bimmerholic]

My fan is driven by the fan belt. Is it my fan got low speed and high speed ? My e39 is 1999 523i. How it works ?

Bro, your fan is not driven by the belt. The fan that you see attached to the front end of your engine is your clutch fan. It is driven by a fluid coupling device that allows the fan to rotate at low or high speed depending on the temperature. The expansion of the bimetallic strip attached to the fan clutch is what engages the speed of the rotation of the fan.

The other fan is known as the AUX fan fitted just behind the grills. This is electrically driven.

Conclusion: No fans in E39 runs on belt. BUT the E39 fans run on RACUN!!!

 

[jarance]

Yes, the Speed of the Aux fan depend on the coolant temperature and aircon pressure.

Extract from BMW WDS

Electric Fan
Vehicles with M62TU, S62 and M73 engines feature a clutch fan as well as an electric fan. The electric fan cuts in when the cooling capacity of the clutch fan is no longer sufficient.

The electric fan is activated by means of a power output stage directly on the fan motor. The motor control unit activates this power output stage by means of a square-wave signal with duty factors (variable pulse width) between 10 % and 90 % thus controlling the various speeds of the electric fan. Pulse duty factors less than 5 % and greater than 95 % do not trigger activation but rather they are used for fault detection purposes. The power output stage features its own positive and ground supply.

The fan speed is influenced by the coolant temperature at the radiator outlet and the pressure in the air conditioning system. The fan speed is reduced as the vehicle speed increases.

If a fault occurs during operation a corresponding fault code will be stored in the fault code memory of the DME control unit.

For the purpose of checking operation and troubleshooting, the diagnostic program offers the option of activating the electric fan directly via the DIS tester/MoDiC

Specified values, pressure sensor
Data on working ranges and substitute values.

The pressure sensor receives a 5 volt power supply from the control unit for the heating/air-conditioning system. The sensor signal is evaluated with the help of tables and forwarded to the engine electronic via the K bus. In the process, the refrigerant pressure in the air-conditioning circuit is converted to a load torque and the required fan stage.

Refrigerant pressure-fan stage conversion table

Each fan stage that is determined is transmitted via a BUS from the engine electronics.
Prerequisite is a speed less than 80 km/h.

Pressure in bar - Fan stage
8--------------------0 (Stop)
10-------------------1 (Slowest Speed)
14-------------------2
15-------------------3
17-------------------4
18-------------------5
19-------------------6
19-------------------7
20-------------------8
21-------------------9
21-------------------10
22-------------------11
23-------------------12
26-------------------13
29-------------------14
> 29----------------15 (fastest speed)

 

[JFT63]

Conclusion: No fans in E39 runs on belt. BUT the E39 fans run on RACUN!!![/QUOTE]

:4::tee:

 

[lwloh]

Conclusion: No fans in E39 runs on belt. BUT the E39 fans run on RACUN!!!

:4::tee:[/QUOTE]

i like this quote. haha.

 

[bimmerholic]

That was randomly written at the end of the explanation. It just kicked in how true we fans are on RACUN!!