At 107C message engine overheated message

[rajdeep]

Hello Friends, 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.

Any help is demystifying this issue is much appreciated.

Thank you.

[rajdeep]

I would like to add 1 more thing, I have coolant temperature displayed in my car and even after driving for 30 mins, the the thermostat does not open allowing the cooler coolant in(the thermostat and upper/lower coolant sensors are brand new). The temperature hovers around 107C. Any ideas?

[jclausen]

What brand thermostat did you use

[rajdeep]

Whaler thermostat.

[rajdeep]

Also I have noticed that the radiator Fan does not come on after I get the "Engine has overheated" message. Only after I start the AC, the fan comes on. I can still drive the car with no loss in power or steam issues. Any ideas?

[rajdeep]

Another observation, when I crank up the heater, the cabin gets pretty warm, so that shows the heater core is ok.

[billr99]

I know you have mentioned that you are seemingly getting good flow thru the system, but it sounds to me like you might have lost some or all the blades off the water pump impeller. If you still have the OE pump, they have composite blades. I had a Volvo R that had had its metal-bladed OE pump replaced with one that had composite blades. Shortly after I bought it, I started having symptoms of overheating exactly like you are describing. I was baffled as I assumed the pump had been replaced by a pump with OE-type metal blades. I quizzed a mechanic I knew and he said that my symptoms, like yours, sounded like what he had seen numerous times with VWs and Audis that also have composite pump blades. Anyway, I pulled the pump and it had no whole blades left. Not sure what caused it but it was obvious that a blade had failed and taken the rest with it. Replaced the pump and all was back to normal.

Anyway, thought I'd mention it as a possibility since your symptoms are what I have seen before.

Good luck!

[rajdeep]

Thanks for your response. My water pump was replaced with the one with Metal blades. So that "hopefully" should be ok.

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Any radiator fan fuse or relay should I check for possible issues?

[rajdeep]

I was able to trigger radiator fan at full blast using the BMW ISTA plus software. Is there any other DME or module should I look into to get a better insight into this heating issue?