Auxiliary fan appears dead - simple diagnostics - 2006 3.0

[jsoto]

Originally Posted by upallnight

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.

thx. Debating whether to have the evac/recharged.



Probably would have diy the aux fan@home if I knew it was shot. I'm not the type to just bring it to a indy for diag. They have to pay for tools, etc, so my approach if it's going to ~the shop~, the work will be done at the shop. I want the indy to be in business....hence why would I have a need for him.

Ended up with alot more than I thought I was going in for. I knew I was in for intake or coil issue and s a unplanned oil sensor change that I had planned for the next oil change DIY. More work to the bill of tab is fuel vent valve and lucky me, but the window reg. broke when they had the window down....

So $125-$150 saved is $125-$150 spent elsewhere if I don't do the evac/recharge

AC was blowing cold when I drove it on the weekends *not enough seat time*
Wifey says she did not notice the AC being warm, except for one instance when she was parked streetside and it was running for like 20 minutes idle.

Now that I think about it, there was one instance where I felt the blower ~spit~ some water at me, but I literally chalked it up to heatwave related weather and ac just getting all that condensate out .

[upallnight]

Originally Posted by jsoto

thx. Debating whether to have the evac/recharged.



Probably would have diy the aux fan@home if I knew it was shot. I'm not the type to just bring it to a indy for diag. They have to pay for tools, etc, so my approach if it's going to ~the shop~, the work will be done at the shop. I want the indy to be in business....hence why would I have a need for him.

Ended up with alot more than I thought I was going in for. I knew I was in for intake or coil issue and s a unplanned oil sensor change that I had planned for the next oil change DIY. More work to the bill of tab is fuel vent valve and lucky me, but the window reg. broke when they had the window down....

So $125-$150 saved is $125-$150 spent elsewhere if I don't do the evac/recharge

AC was blowing cold when I drove it on the weekends *not enough seat time*
Wifey says she did not notice the AC being warm, except for one instance when she was parked streetside and it was running for like 20 minutes idle.

Now that I think about it, there was one instance where I felt the blower ~spit~ some water at me, but I literally chalked it up to heatwave related weather and ac just getting all that condensate out .

I would wait until you install the new fan and see if the AC doesn't work better in stop and go traffic before evacuating and recharging the system. AC system doesn't need to be evacuated to change the aux fan. The front bumper needs to come off and the metal bumper behind it needs to be loosen (I remove mine) just to remove the air direction shrouds on either side of the condenser. Once the shrouds are removed the bolts that secure the condenser to the front radiator frame can be removed.

It's a lot easier to remove and install the bumper cover if you have another person, but since I didn't have another helper I used an inflatable towable tube to place the bumper cover on so that I wouldn't scratch the paint.

[dkl]

Originally Posted by dkl

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.

Just scanned the car (using BMW Scanner 1.4) - no fault code for the AUX fan. Doing a realtime scan on the AC unit and all functional. So now I'm baffled as my AUX fan don't come on with the AC as some of you guys have indicated that it should but I don't have any faults on my system The AUX fan does run when the radiator is hot enough, just not when turning on the AC.

[upallnight]

The aux fan comes on when the high side pressure sensor indicates to the DME that the high side pressure is rising. The fact that you don't have a fan fault after a scan and the fan does come on when the engine temp is hot means the fan is fine.

You could be low on refrigerant. To determine this you will need to connect a set of manifold AC gauges to the system and read the low and high side readings and note the ambient temperture.

[jsoto]

Just for clarity or the wiki, I recall the aux fax was supposed to turn on for a few secs. on startup just to tell the DME was good, but as well, I was under the impression the aux fan literally engages once AC was on

[upallnight]

Originally Posted by jsoto

Just for clarity or the wiki, I recall the aux fax was supposed to turn on for a few secs. on startup just to tell the DME was good, but as well, I was under the impression the aux fan literally engages once AC was on

The DME does spin the aux fan at start up, but the aux fan does not come on the minute you turn on the ac. For example, if you were driving on a highway, the air passing through the condenser is enough to cool the refrigerant in the condenser so the aux fan will not come on. It is only when there is not enough air passing through the condenser that the aux fan will come on.

[dkl]

Originally Posted by upallnight

The aux fan comes on when the high side pressure sensor indicates to the DME that the high side pressure is rising. The fact that you don't have a fan fault after a scan and the fan does come on when the engine temp is hot means the fan is fine.

You could be low on refrigerant. To determine this you will need to connect a set of manifold AC gauges to the system and read the low and high side readings and note the ambient temperture.

Appreciates the inputs and clarifications

[fiataccompli]

as promised, I'm updating. Originally, I thought I'd end up a bit delayed in replacing the fan, but another overheat (upthread) along with a decent amount of OK feedback on one of the non BEHR fans pushed the decision to go ahead & replace the fan. Did it yesterday (timed to be waiting as UPS walked up with the new TYC fan) with a bit of consultation of a couple youtube videos the verify the loosening of the front bumper (of which I was not believing at first). Anyway, it appears to have completely returned the AC to proper function to freeze you out of the car and we now have a day of normal use (I told my wife to put it through it's paces but keep an eye on the temp) so far. I'd heard some comments about noise of the TYC and that is a non-issue on this one (maybe the engine is loud, maybe the old fan -OEM, btw - had bad bearings the last I heard it). Fit was as the OEM and the job itself if rather easy...actually super-easy, just tedious.

I also got a thermostat, but decided to be a bit more scientific since I had no scan indication of a thermostat problem...it was simply one of those things that is probably a good idea & without the fan having failed, I would have suspected a periodically sticking thermostat as the culprit. I guess the fan is for the next rainy day.

I've heard some comments about these fans failing & burning the car. As long as there is no human injury & it's not parked to close to one of my Fiats, that would not be a terrible thing as the X5 is insured and we are comfortably "right side up" in our investment....though, I'd prefer it simply continue to be a good car for the family - whether that continues to be my wife, or we give it to my daughter.

oh, the scanner was a little glitchy in installation. I gather that the instructions regarding WHEN to attach the scanner & when to attach it to your car need to be followed closely. I had a brief period of Windows XP (SP3) (gotta love the old junker laptop!) hanging up even when I had pointed it to the correct driver. I think I ended up loading a driver from a link in Bimmerforums (and there was also a nice software link to dropbox, but I did not end up needing it), but it ultimately installed correctly and was able to read everything. I did, in fact, have a fan fault (no blown fuse, by the way).

Thanks all of you for your feedback/directions/time on this one. I hope the thread proves helpful to someone else.

[Qsilver7]

Just an FYI for those that questioned why their aux fan didn't come on when the AC was initiated...as already mentioned by others...since the debut of the M52TU, M54, & M62TU engines, the aux fan has been the "variable speed" type...and unlike earlier engines used in the M62 & M52 engines (prior to 9/98)...the aux fan doesn't turn on immediately when the AC button is pressed.

The 2-speed & 3-speed aux fans used in the e38 & e39 between 1995-9/98 did turn on when the AC button was initiated...but the variable speed aux fan waits until a PWM signal is sent from the DME/ECU after certain criteria is met (along with a quick aux fan check at start-up):