Engine overheated and shut off

[bigwave2255]

seen this before, a dealer i knew used to go start each car and leave it idling until one blew the motor.

man i know you must be suffering but i have to ask why would you do that, leave the car unattended idling??

its not like your in a cold climate are you??

i think your hand book tells you to not do that, but to get in and start driving from the get go. just take it easy till it warms up,

bit late now i know, but once you get it sorted i wouldnt be doing that again

[R.C.]

Slick, All I know is when im done fixing this i still have the transmission to get to! one good thing I did was set up a wholesale account at my BMW dealer today. Spent 96 bucks on a coolant tank and temp sensor that should have been around 160. BigWave, Most of the time it warms up for 5 mins and im driving. Monday i got sidetracked for 15 mins. I think my coolant tank just failed and boiled the coolant out. I had to replace the tank in my M3 a few months back because one of the little vent hose barbs broke off when i touched it changing the oil. i've read alot about these tanks failing. Im hoping thats what caused this. Started working on it tonight scoped 2 cylinders and they look good ill do the rest tomorrow. drained the oil, no water in it. Also pulled the temp sensor and thermostat for now. One good thing is it started right up and ran smooooth for the minute it took to get it on the trailer and off when i got to my shop. keeping my fingers crossed that everything goes good tomorrow. Ill let you know. Thanks again for the input guys.

[R.C.]

Well I finished scoping the rest of the cylinders and they all looked fine. Did a compression check on all cylinders and they where all around 180 PSI accepte # 5 it was at 155 PSI. Changed the 2 temp sensors, pump, tank, thermostat, oil, filter and spark plugs to E3s. Started it up and ran it for about 45 mins checking the temp with my IR temp gun. It never got above 165 but the temp gauge in the dash is still all the way on hot. When I turn the key the gauge moves to cold and as soon as the engine starts it goes right over to hot. Not sure what else to look at. Any ideas? Everything is working the fan comes on it runs fine and it's not making any funny noises. I tried disconnecting the battery for about 10 mins but the temp gauge is still not working right. Going to take it to get it scanned and hope that tells me what I need to know about the temp gauge.

[TwinsPoppa]

Originally Posted by R.C.

Well I finished scoping the rest of the cylinders and they all looked fine. Did a compression check on all cylinders and they where all around 180 PSI accepte # 5 it was at 155 PSI. Changed the 2 temp sensors, pump, tank, thermostat, oil, filter and spark plugs to E3s. Started it up and ran it for about 45 mins checking the temp with my IR temp gun. It never got above 165 but the temp gauge in the dash is still all the way on hot. When I turn the key the gauge moves to cold and as soon as the engine starts it goes right over to hot. Not sure what else to look at. Any ideas? Everything is working the fan comes on it runs fine and it's not making any funny noises. I tried disconnecting the battery for about 10 mins but the temp gauge is still not working right. Going to take it to get it scanned and hope that tells me what I need to know about the temp gauge.

Hmmm, if you changed the temp sensor and you're still getting a false reading then I would think its either the gauge itself or something in the wiring is off.

Did you try and see what the temp gauge will do with it disconnected from the sensor? You would think it would not move at all but if it has the same behavior then that should confirm its not the sensor.

Assuming nothing wrong with the gauge or sensor, I'm thinking maybe its not grounded properly or something in the wiring is shorting/loose.

[R.C.]

I did check it with the sensor unplugged and it did the same thing. in the big red book it shows the sensor, a/c, fan, temp gauge and other things plugged into an ECM. I'm thinking ether the ECM needs to be reset using a scan tool or the ECM or gauge is bad.