Just cool it! M62TU cooling system -> 88 deg thermostat and PWM elec fan conversion

This thread is about my M62TU cooling system modification with an 88 degree thermostat and PWM controlled electric fan.

Having just completed a supercharger installation, and having grown tired of the immense heat that the M62TU puts out over the time I've owned it, I went searching for a way to lower the regular operational temps. Came across a thread here on bf.c about an X5 diesel 4.4L that uses an 88 degree thermostat that bolts in, so I ordered one from Europe:





Some comparison photos between stock 105 C and euro 88 C:







Took the old one out and the new one bolted in easily:



Now that that's done, let's move on to the electric fan. I went with an Auto Cool brand PWM fan controller that has an option for allowing the fan to remain on after you turn the car off to further cool the car down. Let's get started.

First off I put an external brass temp sensor on the VF metal coolant hose and covered it with some rubber to isolate the sensor from the fan's blowing air and other temps. The gray is the rubber and yes, I zip tied it in place:



I did this as a quick check to see how much clearance I had between the VF pipe and the AC compressor pulley:



Next, as you know, there is a "Cake Pan" modification thread started by fmzip on this board. I bought the cake pan from Amazon and modified it per the thread, but it's too small to bolt directly to the M62TU shroud (the pan measures 18" in diameter and the shround is more like 19 3/4" diameter). So I had to get creative. I bought some 1" aluminum bar stock from ACE hardware and had my neighbor help me weld standoffs for mounting. You can see them here (there are four and they were tricky to get lined up and sized properly):



More test fit images:







After quickly bolting everything up, I dropped it in the car to make sure there weren't any clearance issues. It fits! So next I moved on to actual installation.

I used Weatherpak connectors to make a quick and easy way to disconnect the shround/fan as a single assembly for future maintenance:





Here's my controller with all the pigtails I custom made ready to go in. There are a few grounds, the fan connector, and a fused power lead (20A) that I will connect up to the aux fan's constant 12V power. I used OE style Tesa electrical tape to wrap all the wiring for an OE appearance.



Here's the controller mounted on the driver's side shock tower facing front:



I used the existing nearby ground strap for the smaller ground leads:



Here's the tap into the big fat power wire at the aux fan (it helped to remove the headlight):



Plug the fan in:



and, it's done:



I'll probably paint that unsightly mounting bolt on top of the curved part of the shroud but for now I was going for function over beauty and it seems to fit nicely.

While I was in there I replaced the aux water pump and am hoping that helps the bleed process go more easily.

Testing to commence just as soon as I get my Umnitza headlight (one is missing) in from USPS and finalize the M5 fuel pump upgrade.

Just cool it! M62TU cooling system -> 88 deg thermostat and PWM elec fan conversion