Auxiliary fan appears dead - simple diagnostics - 2006 3.0

[upallnight]

If the mechanic saw a trouble code for the aux fan, then the aux fan is bad.

Here's a scan of an X with a Fan Fault.

[jsoto]

Yeah. I saw that thread.

Probably on his Autologic, he told me he tried turning it on and it would not turn on.

I did ask him, odd, as we never noticed it not producing AC.
I suppose either driving conditions allowed compressor to run.
Texted her later in the day and she did say it was a bit mild once during parked and running. She assumed it was just the heat and AC not being to handle it.

Would the high pressure cutoff occur or how would one know if it did purge out some refridg. Just short of confirming by a vac weigh

[upallnight]

Originally Posted by jsoto

Yeah. I saw that thread.

Probably on his Autologic, he told me he tried turning it on and it would not turn on.

I did ask him, odd, as we never noticed it not producing AC.
I suppose either driving conditions allowed compressor to run.
Texted her later in the day and she did say it was a bit mild once during parked and running. She assumed it was just the heat and AC not being to handle it.

Would the high pressure cutoff occur or how would one know if it did purge out some refridg. Just short of confirming by a vac weigh

High pressure cutoff will occur if the high side is above the designed level. The power to the compressor will be removed by the DME so that the high side doesn't go any higher. With the compressor not running eventually the pressure will start to go down. As for how to determine if the system actually lost refrigerant if it did a purge, you will need to evacuate the system and see how much refrigerant was recovered base on what it should have been.

[fiataccompli]

OK, I will have test equipment in hand this evening for our X5. I have two related questions...

1. Would/could/does the failure of this fan to engage lead to overheating? This morning, while waiting in a stopped traffic (probably >5 minutes) & with the AC NOT ON, the temperature rose. There is no leak detected & the thermostat seems like a likely component to suspect (or simply replace, since it's relatively inexpensive, not hard to get to & could be 10 years/164K old).

2. I checked RockAuto out of curiosity this morning & they have the following array of fans that are substantially less costly than the BEHR....Are these fans fraught with danger?
(I know someone already mentioned steer clear of Dorman)

TYC 611400 $156.79 ( I noticed Bavarian Auto also sells this..but for $219)
DORMAN 621213 $175.79
FOUR SEASONS 76164 $298.79
VDO FA70744 (no price...out of stock)

(and I suppose I should ask the same of the thermostats at RA, but those choices seem to be the same array as the common BMW vendors.

thanks again for the feedback.

[upallnight]

Originally Posted by fiataccompli

OK, I will have test equipment in hand this evening for our X5. I have two related questions...

1. Would/could/does the failure of this fan to engage lead to overheating? This morning, while waiting in a stopped traffic (probably >5 minutes) & with the AC NOT ON, the temperature rose. There is no leak detected & the thermostat seems like a likely component to suspect (or simply replace, since it's relatively inexpensive, not hard to get to & could be 10 years/164K old).

2. I checked RockAuto out of curiosity this morning & they have the following array of fans that are substantially less costly than the BEHR....Are these fans fraught with danger?
(I know someone already mentioned steer clear of Dorman)

TYC 611400 $156.79 ( I noticed Bavarian Auto also sells this..but for $219)
DORMAN 621213 $175.79
FOUR SEASONS 76164 $298.79
VDO FA70744 (no price...out of stock)

(and I suppose I should ask the same of the thermostats at RA, but those choices seem to be the same array as the common BMW vendors.

thanks again for the feedback.

You should have a mechanical fan attached to the water pump, in addition to the aux fan. Unless the mechanical fan is also faulty, your X shouldn't be over heating with the AC off.

A scan of the X with BMW Scanner 1.4 or any BMW specific scanner will indicate the fan fault and a bad thermostat.

I wouldn't be driving the BMW until you get the overheating issue under controlled or else you risk warping the head which will be an even more expensive fix.

If people just wants to drive a cheap car why do they buy a BMW and use cheap parts on it?

[fiataccompli]

well, some parts that compose a BMW are a bit pricier or complex than is needed to do the job. I can't expect everyone to agree. Not sure I drive...well, I don't, actually...a BMW because it is a certain type of car. Actually, that "image" is probably the one thing that keeps me from becoming a true enthusiast for the brand - ha! They are nicely designed but in many cases I think over-designed to the point of diminished returns on the complexity involved. But that's a different topic.

Until this morning, I thought the X5 was in the clear in terms of risk of overheating. Unfortunately, that wasn't the case, but fortunately my wife who was driving quickly shut the car off and thus risk was reduced. Faults will be scanned this evening with the proper gear & quality parts will replace those found to have failed. Whether there has been internal damage wrought on the car is something only time will tell, but that's life.

regardless of any editorial opinion, I'm still interested in hearing if anyone has some actual long-term experience with various other fans. My experience with repairing/maintaining/restoring cars has led me to notice there are varying levels of sensitivity with the type/quality of replacement parts. Thus as a vehicle begins to approach the waning end of its anticipated useful life, I'm mindful of that....the extreme being some old pickup trucks I've owned where buying a tank of gas may be a questionable investment!

I gather that (as I would suspect) aux fan failure should NOT lead to overheating.

thank you all again for the time & space here!

The radiator fan - traditional front of engine, clutch type - is intact & appears to work....though you mention it & I suppose some clutch/slip issue with its engagement could be a problem also. Should this also ping a code?

[richardb]

Upallnight has some great answers in this thread. I agree, the car should not overheat with a bad auxiliary fan. Our fan was bad and the car did not overheat even in hot summer traffic. It did however effect the AC; it would only blow cold while moving along at speed.

I recently replaced the aux fan with an aftermarket TYC brand from Amazon and it is of very good quality. I believe the expensive Bosch unit is also made in China or Taiwan, but over twice the price. I'll report back the long term reliability when I can.

https://youtu.be/N_K0KPHsteA?list=PL...BoZOPEauRHskow

[fiataccompli]

Since I rarely drive the car, I was relying on my wife's description. According to her, these recent issues all began when without warning the expansion tank blew up dramatically and it overheated (and she parked & rented a car). She said she had not noticed any AC issues until after the tank (and the thermostat that sits in the bottom
Of it ) was replaced. It overheated again (also, immediately grounded) and I thought it was my own fault due to inadequate "burping" of the coolant...but with that checked & double checked & no apparent external or internal coolant loss but another overheat today, clearly I need to check other stuff and the thermostat is the first stop.

I did actually drive the car a good bit over the last week to try to put it through its paces, basically trying to bring it to a failure point if it were to reach one, but it seems my wife had the special touch on this one!

[dkl]

Originally Posted by richardb

Upallnight has some great answers in this thread. I agree, the car should not overheat with a bad auxiliary fan. Our fan was bad and the car did not overheat even in hot summer traffic. It did however effect the AC; it would only blow cold while moving along at speed.

I recently replaced the aux fan with an aftermarket TYC brand from Amazon and it is of very good quality. I believe the expensive Bosch unit is also made in China or Taiwan, but over twice the price. I'll report back the long term reliability when I can.

https://youtu.be/N_K0KPHsteA?list=PL...BoZOPEauRHskow

Thanks for the DIY video. My AUX fan doesn't run when I turn on the AC (only the main fan spins and AC is working as expected), but I know it isn't dead because it does kick on when the car is hot. Most days it stays on for a few minutes even after shutting down the car. Does this means my AUX fan is only half functional?

I'll run a scan tonight to see if there's a fault code for the AUX fan.

[fiataccompli]

Originally Posted by dkl

but I know it isn't dead because it does kick on when the car is hot. Most days it stays on for about 5 minutes even after shutting down the car. Does this means my AUX fan is only half functional?

THIS is what gets me confused because it appears that the fan is operating to assist (a pusher fan...makes sense, right?) the main radiator fan. Guess i'm just thinking out loud at this point because I know two parts that are about to replaced on our X5...