Pretty much what I figured. I'll replace it next week and report back :thumbup:

Just want to report back that I replaced the thermostat today and am now running at a consistent 188-190F, or 88C. Thanks to everyone here the whole process really wasn't that bad. If I were to do it over, I could probably do it in under 3 hours. I did wind up with a coolant leak from a hose off the new Tstat and had to dive back in to refasten it, but it wasn't actually a huge deal. :cool:

I just change my thermostat at only 39k miles on my 09. So this is more of an age thing than a mileage thing. My old thermostat had good days and bad days. A bad one would be stuck around 75 degrees and a good one would stick at 83. So don't monitor for one trip and assume you are good or bad. I am in FL and it is still in the 70s here so my bad low reading would probably be lower if I lived in a normal part of the country.

Just completed a thermostat replacement on my 2010. Was regulating to about 72DegC(161DegF). Nice boost in mileage of about 2 L/100Km after 1st tank city & hwy.

FYI, I did not remove my fan to replace the thermostat.

Removing the top reinforcement bar and the fan is the easiest thing to do. The fan housing has a foldable tab on one side so it slides up in just seconds.

Wow!How did you do that without removing the fan? That area is so tight.Did you reach out the thermostat from the bottom side?did you remove the egr cooler?

Yes it does make a difference in fuel economy especially if your old one was maintaining under 75 deg C.It's because engine remains in a Rapid warm up phase and injects more diesel until it reaches normal operating temperature.That's what I read in BMW technical documents.

Got in there with various deep sockets and/or short extensions. Had enough room to fit my air ratchet in there although that isn't required for the job. Just speeds up the process.

EGR cooler comes out first then I removed the thermostat from the top.

Were you able to replace the oil cooler thermostat without removing the radiator &/or fan shroud?

Well done. All of you BMW diesel drivers should check the thermostat and the glow plugs. You can end up like this one if you drive aroung with cold engine :(

http://www2.pic-upload.de/img/29310537/IMG_1861.jpg

http://www2.pic-upload.de/img/29310546/IMG_2148.jpg

http://www2.pic-upload.de/img/29310545/IMG_2131.jpg
https://yadi.sk/i/YDAdKZZfmeKhQ

Melted piston!!!?!!?! Was that a leaky injector? What makes you link it to a thermostat?

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