I posted this on another thread first week of october
http://x3.xbimmers.com/forums/showthread.php?t=1160245
"This just happened to me for the first time. I searched this forum which lead me here.
I was driving 50 miles into a 100 mile weekend highway drive, my overheat alarm went off - never happened before. The temp gauge was at or just above the 250F mid point. it seems like it usually about the 3/8 mark up to just under 250 - never touching it in the past, but I don't look at it all that often.
today when this happened, the computer cut power to the engine, i pulled over, shut down. first i restarted to see if it was just a sensor, still overheat alarm, so i shut down let it cool off for 5 mins - no steam or leaking fluids, and after 5 mins or so I started backup, no alarm, gauge was down some. At first I was going to drive just far enough to get off the highway like the next exit with service, but everything seemed ok and i completed my drive there and back later on
on the rest of the drive to where I was going, temp gauge seemed a little closer to 250 than normal - at one point i thought it was going to hit 250, alert me and I was going to replay the cool down on the side of the road as described above. never happened, i made it no problem other than a little nervous.
on the way home later tonight, 96 miles, no problems. at or just above 3/8 mark the whole way - i must say i paid more attention to that gauge today than in the last 5 years combined.
After seeing this i'm confident if it happens again I can pull over and cool down without overheat.
I may see if it happens again before seeking service - not sure, will be going to a shop for tires in a week or so - not sure if dealer or indy - my service center has a deal on install/mount that may actually be cheaper - more on that on a tire thread.
looking at the repairs some of you have done, it would seem to make the most sense to just replace the thermostat if it starts happening again would prefer to not replace the pump unless thats really going to fix it. this problem really seems like a stuck thermostat - seems like a more common problem long ago.
also, looks like this thread is mostly 35i's ?
mine is 2011 35i w/ 56k - very few issues in 5 years."
had a pretty quiet month - no issues, but i would notice a fan or pump motor running on and off and at odd times under the hood. actually made service appt for Weds anyway based on the motor/pump running. I hadn't driven anywhere of distance since. Well this past Saturday - i drove 200 miles round trip - had to pull over a few times w/ engine high temp warning - only thru the onboard computer - temp gage (which I believe measures engine oil temp) was normal (below half) and every time i pulled over I would hear the pump motor running like crazy. but ever sitting a minute or 2 i could restart and continue on.
only doing light local driving until my service appt weds, I suspect my 2011 35i is next for a new water pump though
Let's hope the extended powertrain warranty covers it. 57.5k I have some more road trips coming up, needs to be fixed. stay tuned.
Greg