One of the first things I did when I got my '01 X5 in May '21, was to replace the mechanical fan with a 3000 cfm aftermarket electric fan, which I configured to automatically switch on at a specified temperature, using a thermostatic switch. It worked great like that, but I wanted more control (always), so I installed a motor speed controller that allows me full control (the thermostatic switch is still in effect, or I can go full manual, via another switch. I tend to turn the fan off at highway speeds, limit its' speed to 75 or 90% in cold weather or at stoplights (reducing the noise).

But, knowing how fragile aluminum engines are (I'm from the days of robust, all-cast iron Chevy V8's), I didn't want to trust a thermostatic switch to turn on the fan, or the weird in-dash temperature gauge that BMW uses, to tell me when to do so, if the T-switch failed. So, I use a dash-mounted 8" Android tablet to run the Torque Pro app, so I can see the ACTUAL coolant temperature (and other parameters, of my choice) at all times. I could've used an Android radio and a Resler adapter to do the same, but I couldn't see buying a new radio and adapter, when my radio was also new, and I had a spare tablet.

The previous owner refreshed the cooling system about 1000 miles before I got the X5, and I've only put another 2k miles on it since, so I'm pretty sure that it's good for awhile. But, I'm constantly underhood checking on things, so I'm keeping an eye on it, too.

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01 BMW X5 E53,3.0i-5L40E, 7/13/01
topas-blau,Leder-grau,"resto-project car"

Here:
14 Lexus ES350,3.5L-U660E
09 HHR Panel,2.2L-4T45E
04 Chevy 2500HD,6.0L-4L80E
98 GMC Sierra 1500,5.7L-4L60E

Gone:
66 Chevelle Malibu 2dr ht.,327>441c.i.-TH350>PGlide/transbrake
08 Cobalt Coupe,2.2L-4T45E
69 & 75 C10s,350c.i.-TH350
86 S10,2.8L-700R4
73 Volvo 142,2.0L-MT4
72 & 73 VW SuperBeetles,1.6l-MT4
64 VW,1.2l-MT4
67 Dodge Monaco 500 2dr ht.,383c.i.-A727
56 Chevy 210 4dr,265c.i.-PGlide