Temp. gauge a little past middle piont

[upallnight]

Originally Posted by cchino623

So i have a question M5James, If the Aux Fan in front is not working then could that be the reason my X5 begins to overheat in slow moving traffic as opposed to driving on the highway without traffic?

Do you have the AC on in traffic?

[hunds02]

Originally Posted by m5james

I haven't touched on some of these threads in years, so I might not know what I'm talking about...but with that said. I'd think you can do it via a process of elimination. Swap relays around with another of the exact same size, style, color, etc and see if anything changes. As for the fan itself, it's just a 12v motor that you can jumper directly to your battery, or I've even used 18v batteries from my power tools to test the fan I bought for my Harley F150 e-fan conversion.

Thanks m5james, I will test with a multimeter and post afterwards. I also realized that if you are a broke college student, like me, you can simply remove the entire shroud until you decide to buy a new one. Removing the shroud is better than having a faulty pusher fan. This way more air hits the radiator and cools it down more effectively rather than air hitting a stationary fan that does not work.

[m5james]

Even if you don't have a multimeter, it's still just as easy to swap the relays and go from there. This is just me, but if you're overheating at all, but you insist on driving, I'd learn to accept the idea that when you do drive that you need the heater running full blast to help dissipate the heat. There are hundreds if not thousands of stories of failures of the engine and/or cooling system in most any BMW due to all the plastic used.

Coming from a guy who's lost an engine in his M5 from stupidly removing the seized fan clutch (being a broke college student, forcing the sale of a car with a brand new paint job too) to the engine in my 740iL eating itself alive because the previous owner half-assed the head gasket repairs only after he half-assed the cooling system ($13k after replacement after all said and done), I can't preach enough about never letting your engine get to hot...I'll crank the heat in the summer and sweat if I were you until you can force replacement parts into your budget. Really...don't drag your feet on this one, a potentially $200 fan is cheaper then the expenses and extreme inconvenience of losing a motor because your budget includes lattes every morning instead of keeping your Big Money Waster up to snuff.

[hunds02]

Originally Posted by m5james

Even if you don't have a multimeter, it's still just as easy to swap the relays and go from there. This is just me, but if you're overheating at all, but you insist on driving, I'd learn to accept the idea that when you do drive that you need the heater running full blast to help dissipate the heat. There are hundreds if not thousands of stories of failures of the engine and/or cooling system in most any BMW due to all the plastic used.

Coming from a guy who's lost an engine in his M5 from stupidly removing the seized fan clutch (being a broke college student, forcing the sale of a car with a brand new paint job too) to the engine in my 740iL eating itself alive because the previous owner half-assed the head gasket repairs only after he half-assed the cooling system ($13k after replacement after all said and done), I can't preach enough about never letting your engine get to hot...I'll crank the heat in the summer and sweat if I were you until you can force replacement parts into your budget. Really...don't drag your feet on this one, a potentially $200 fan is cheaper then the expenses and extreme inconvenience of losing a motor because your budget includes lattes every morning instead of keeping your Big Money Waster up to snuff.

$200?
Find me a pusher fan for $200 and I will purchase it in a heart beat.
I think they go for around $400 aftermarket (for BEHR).
Also, please don't assume I am an idiot, I am a mechanical engineer, currently pursuing my masters. I don't run the AC in traffic, I know that will overheat the system, I only have the AC on when I am cruising over 50 mph. Plus my car's temp gauge has never exceeded the half-way mark, and if it ever did, then I would crank the heat.

[m5james]

Haha...I so didn't mean it the way you're taking it. I don't know what the fan costs, that's why I made a guess. I'm just trying to stress don't push the system, and don't trust the needle either...by the time it moves, there is like a 30-40 degree difference, so I'd say to unlock the OBC on the cluster and don't let it get over 110-113* Celsius at most.

[hunds02]

Originally Posted by m5james

Haha...I so didn't mean it the way you're taking it. I don't know what the fan costs, that's why I made a guess. I'm just trying to stress don't push the system, and don't trust the needle either...by the time it moves, there is like a 30-40 degree difference, so I'd say to unlock the OBC on the cluster and don't let it get over 215-220* Celsius at most.

Will do, thanks again for your input

[srmmmm]

Use care when testing your aux fan. It's protected by a 50amp fuse and can pull a lot of electrical power. Mine burned up after the dealer failed to reinstall the mechanical fan when they changed the alternator.

2002 X5 3.0 236,000 miles
2004 325i 105,000 miles

[TerminatorX5]

Electric Fan

Vehicles with M62TU, S62 and M73 engines feature a viscous fan as well as an electric fan. The electric fan cuts in when the cooling capacity of the viscous 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.

Electric Fan DDE 4.0

The DDE control unit activates the electric fan by means of a square-wave signal with duty factors (= variable pulse width) between 5 and 90 % and thus controls variable speeds of the electric fan. The electric fan features its own positive and ground supply.


Troubleshooting

The activation function is monitored for short-circuit and open circuit but not the fan motor itself. Fault code 0480 "Electric fan" is stored if a defect occurs.
Consequence: Engine temperature increases
The fault code entry "electric fan, short to ground" may be caused by a mechanically blocked fan motor (in winter by frozen condensation water).
Note: As from 03/00 mechanical blocking of the fan will be detected as such and the type of fault “Electric fan mechancially blocked” will be stored.


Specified values, pressure sensor

Data on working range 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 telegram from the engine electronics. Prerequisite is a speed less than 80 km/h.

Pressure in bar _________ Fan stage
8________________________0
9________________________1
11_______________________2
13_______________________3
14_______________________4
15_______________________5
16_______________________6
17_______________________7
18_______________________8
19_______________________9
20______________________10
21______________________11
22______________________12
23______________________13
24______________________14
> 24____________________15

Electric fan DDE 5.0/5.1

The DDE control unit activates the electric fan by means of a square-wave signal with duty factors (= variable pulse width) between 5 and 90 % and thus controls variable speeds of the electric fan. The electric fan features its own positive and ground supply.


Troubleshooting

Faults in the control of the electric fan and on the fan itself are monitored. The following faults can be stored:

• 41F0, Activation short circuit to positive
• 41F1, Activation short circuit to earth
• 41F2 Activation circuit break
• 41F3, Excess temperature output stage
• 4B20, 4B22, Electric fan jammed

Consequence: Electric fan not functioning, engine temperature rises