XSeries-forum

It appears that the cooling fan has given up the ghost on my X5, I've only owned this car for approximately 8 months and I'm not sure it's ever worked in all honesty.

I use this car to tow our caravan and my track car so it's pretty essential, the fan fitted is rated at 600w but I'm seeing two different fans (600 and 850w) - does anyone know if the 850w fan is interchangeable or what needs to be done to fit this unit as I guess a more powerful fan will be beneficial for towing duties?

Thanks in advance.

Hello &

The 850W fan is fitted (or should be) to any car either fitted with a factory fit towbar or additional towing capacity (3.5T instead of 2.7T). Aftermarket tow bars frequently don’t have it done. Cars with additional towing capacity have an additional fan and radiator in the left front behind a grille.

Possible that you need to uprate the electric fan fuse as well.

Thankyou for your reply, it's not a factory fit towbar so my guess is that it's never been upgraded. My only concern is the difference in current between the two units 50amps v 70amps - just wondered if they are interchangeable and what modifications need to be done to fit the larger unit.

They should be interchangeable and yes you need the fuse uprated. If you have a look in RealOEM and use the last 7 of your VIN in ‘Serial Number’ it will pull up your model. Have a look in Retrofittings and see if there is an uprated fan option listed. If there is, note the EBA number and see if it’s avail on line, or ask you friendly BMW Parts team to print it for you.

RealOEM is a copy of the BMW parts database. If the kit isn’t there, then BMW may still be able to help. The wiring should be fine as they often ‘over spec’ and there’s often only one loom type catering for both. The EBA for a post-build towbar retrofit should have details too. It’s one of the reasons BMW charge more than £2k to retrofit a towbar!

The replacement process may differ with engines but looks like:
Acoustic Engine cover - remove
Front underbody protection - remove
Air intakes (from top of rad area) - remove
Bonnet cable detach from strut brace and remove brace (if there is one)
Disconnect electrics from fan
Might need to remove air pipes for the intercooler
Release the side catches at the bottom of the fan & cowl and lift clear.

Fitting will be reversing the above…..

The aircon may also not work without the fan. That was the case with some versions, and in the E53.

Just put a standard one back will be more than adequate for the uk , you may struggle to get an 850w one unless you buy new . I had my fan out to replace a water pump just this week , there is a swivel clip on the passenger side that needs levered in below the rad hose so you can remove the fan past the hose with out removing hose and there is a torx on the boost pipe bracket needs taking out there too. Unplug the powercable on drivers side push in tabs and it lifts out when you unclip the water hose clipped to it in middle. It sounds easy but its a bit of a faff the left side clip .

Check the power plug on drivers side is actually plugged in first someone may have forgot to put it back and spin it by hand to see if siezed , be careful if engine is hot it can start without warning.
Annoyingly after replacing my water pump and it having some play in the bearing my sd is still losing water ,looks like the rad has a small leak

Just looked it up OEM and it’s €900 for a genuine 850W. It’s a fan, not an aircraft propellor!! Even pattern ones are more than £200, and half decent are the wrong side of £500. Either inflation has gone mad or there’s some serious ‘enhancement’ to prices going on.

Thankyou all for your swift and detailed replies.

Fan is seized, it was plugged in and I have measured 12.5v at the plug and a voltage down at 3.4v on the small wire in the plug.
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Just a side note, I always thought that the a/c was poor - explains it now... Best get ordering one as the caravan comes out next week and the track/rally car needs to be at events..

One of the wires has a Pulse Width Modulated signal so a meter will give you the wrong impression. This signal controls the fan speed and is driven from the fan controller itself. Short pulse - lower speed. Long pulse = higher apparent voltage on a meter and ‘stand by for take-off’ fan speed.

I have seen various YouTube video clips on that, I am pretty happy that the fan is the fault in this case using the information that I have found online. I have managed to buy a 2nd hand one with a short guarantee for a price I'm happy to see what happens. I will post an update in a few days when it arrives and I have had a chance to fit it.

Thank you for your help and replies.

Happy days The cost of some spares is a bit eye watering for sure but luckily there are plenty of used parts about where you can't get a new oem part for sensible cost.

I apologize for the late update, I received a 2nd hand replacement cooling fan unit (purchased from eBay) and fitted it to my X5, after clearing the fault codes the replacement 600w fan works perfectly.

On a side note the old unit wasn't actually seized but somehow a decent sized stone had become jammed up inside preventing it rotating and causing the ECU to register the fault. I have managed to remove this and when plugged in it works perfectly!!

As it's a bit of a fiddle to get in and out the replacement unit can stay, but in total in took a couple of hours and cost me £70 so cheaper than a garage and a lesson learnt. Thank you all for your help with the replies.

I've had mine out a few times now so takes about 5 minutes good result anyway

Before anyone goes and swaps to the 850 watt fan, be warned its not that easy...in fact, the car wont even take advantage of the new fan and may create a fire. The dme controls the fan via a pwm controlled relay (a very large relay) and reads fan rpm to determine strategy based on cooling system sensors.
The pwm controlled relay is located just in front of the right front wheel inside the fender itself. Hard to get to but do-able. It is fed large 10 guage wires and a plug for pwm...the 850 watt relay(called a cut out relay) is different from the 400/600 watt as is the wiring between it and fan.
From mid 2007-up,The JBE feeds primary power to a 60 amp fuse for 400/600 and a 100 amp for the 850watt. Prior to mid 2007 the fan relay was powered off a 100 amp fuse and didn't use a special pwm relay, the fan itself is specific to those years and shouldn't be swapped.

Also, you must change JBE (and possibly another module) coding for 07-up cars and select the 850 watt options to even take advantage of the additional output. Easier to just add the 850watt cooling option to VO and let it update as needed.

JBE - Junction Box?
VO = Vehicle Order (changed via NCS Expert or similar)?

Yes junction box electronics under glovebox. Second fusebox is also at same location.
Vehicle order exists in CAS and also in FRM (footwell module) and is your base options plus additional options..that higher wattage fan is usually found on cars with tow package prep or hot climate version and any V8's or performance engine versions....i e.
S323 Soft-Close-Automatic Doors
S3AG Reversing Camera
S3AT Roof Rails Aluminium Satinated
S3E2 Exterieur-Design Pure Experience
S3MB Indiv. Ext. Line, Burnished Aluminium
S823 Hot-Climate Version