2005 BMW 745 engine overheat message, No CEL error codes
What is your question?
This is regarding 2005 745LI, I have recently changed coolant Thermostat, Upper and Lower Coolant sensor and Radiator fan. I keep on getting Engine overheated at 107C. The Water pump is working fine as I can c a steady stream of coolant in coolant reservoir. The coolant is between Min and Max range (no coolant leak).
Upper radiator hose is HOT and lower radiator hose is warm to touch.
I am able to drive for 30 mins continuously and the message keeps on popping and disappears and this cycle continues.
Also the radiator fan does not come on when the overheating message pops up. Only when I start the AC, the fan starts.
Any help is demystifying this issue is much appreciated.
Thank you.
How long has your 2005 BMW 745Li had this problem?
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I'd be looking at what information is coming into the engine's processor about engine temperature, and the reaction of the fans to that information.
I'm definitely no BMW technician, but that's just basic theory. If you measure and monitor engine temperature and it reaches the threshold that fans should turn on, and there is no cooling fan function - this can lead to overheating, especially if you're not driving at a decent speed that allows for air flow instead.
