Auxiliary cooling fan impending failure?

[Effduration]

One problem with the Aux fan is that there are no codes thrown when it fails. Just stops working.

The clutch fan can also fail and still LOOK like it is working because it is turning. No codes here either.

I replaced my AUX with the TYC (made in Taiwan) Aux fan on Amazon...Good reviews and a lifetime warranty. It was 1/3 the cost of the OEM part. I have been happy with it.

[workingonit]

I had previously stated that I have the fuse and relay (a full box of standard fuses, rolls of 24 and 14 ga wiring, assorted connectors, and electrical & silicone tape, too), for my aftermarket electric "puller" fan, ready at hand, among my ever-growing collection of parts, supplies, and tools carried in the rear of my X5, but I don't have any spare parts that may be required for the auxiliary fan (if/when it fails).

Actually, I don't have any spare maxi-fuses or BMW-specific relays for anything on hand, nor the BMW X5 Auxiliary Fan Switch (that fits in the lower radiator hose), nor the BMW AUC Climate Control Sensor that fits on the radiator/shroud. Not a problem now, with no codes for heating, cooling, HVAC, ever. But...

I need to acquire spares of everything, as I like to be prepared, and knowing the propensity for old BMW's to overheat and warp the aluminum engine (not nearly as forgiving as my old 327 c.i. iron block and heads, that didn't warp after getting to 300 degrees, once... in traffic, in summertime,, when the clutch fan failed 50 miles from home as I drove home from work, in the Chevelle..., but I rebuilt it just to be sure....). Note: I distrusted mech fans after that, and check the ones still used on my trucks on a regular basis.

What else do I need for the Auxiliary cooling fan (the actual cooling system...radiator, expansion tank, water pump were refreshed < 5000 miles ago)?

[wpoll]

Not much (replaceable) can go wrong with the aux fan. It has a 50A or 60A fuse (size and location varies depending on year) but that's about it - when it dies, you need to replace the entire fan.

Having said that, it is rare that an aux fan failure will strand you - the car will still drive fine and stay cool (up to a point!) without it. If you lost the aux fan and were driving in very hot weather, you might have a problem when stopped for long periods or want to use the AC when stopped.

[andrewwynn]

AC won't run at all once fan fails. You can jump start it with the right scanner when driving. I've removed my clutch fan over winters with e53 also no problem. E70 rarely every uses the only fan even when ac is running. The fan is set to 7% duty cycle until you get the ECT hot enough to care.

[wpoll]

Originally Posted by andrewwynn

AC won't run at all once fan fails. ...

That makes sense but I recall folk here with issues with their A/C not working when they stop (i.e. at traffic lights) but it works fine when they are moving.

I guess it would depend on if the DME/DDE registers an aux fan fault and disables the A/C (via disabling the compressor clutch). And I know the DME/DDE tests the aux fan at each start-up cycle, so it should log a fault if the aux fan has failed but...

[andrewwynn]

My experience was that when fan failed the star test I could not engage the AC that start cycle.

That being said, I also was able some times to force the ac compressor on with the foxwell and it worked until I turned the car off that lasted a week or so until I would have to manually kick the AC on with foxwell every minute or so. it was brutal hot out and the new fan took a while in shipping.


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[X5chemist]

Has anyone experimented with closing/covering or removing the small housing flaps?

On my Ram, I removed a few lower air diverters for better highway cooling. Temps don't go above 197F. A cooler thermostat works better too. The stock temp of 203F is way to hot for Texas.

[Clavurion]

Originally Posted by X5chemist

Has anyone experimented with closing/covering or removing the small housing flaps?

On my Ram, I removed a few lower air diverters for better highway cooling. Temps don't go above 197F. A cooler thermostat works better too. The stock temp of 203F is way to hot for Texas.

I can't see how removing those flaps would help, because when fan is running the air pressure will guide part of the flow on wrong direction.

[workingonit]

Originally Posted by Clavurion

I can't see how removing those flaps would help, because when fan is running the air pressure will guide part of the flow on wrong direction.

I've noticed that the flaps will easily move while my 3000cfm electric fan is operating, even while the aux fan isn't. I'm sure that they don't impede much airflow at all; conversely, perhaps even taping them shut might focus more airflow to the main mass of the condenser/radiator?

[andrewwynn]

Originally Posted by X5chemist

Has anyone experimented with closing/covering or removing the small housing flaps?

On my Ram, I removed a few lower air diverters for better highway cooling. Temps don't go above 197F. A cooler thermostat works better too. The stock temp of 203F is way to hot for Texas.

The flaps on the fan housing are to increase cooling when not moving. (To keep aux fan air from blowing out the front vs. though the radiator). If you live in 40c climate bmw makea a high temp version of e53 which should be the only one available. The car is designed to open the tstat at lower temps under load. If that's not working replace tstat.