Phantom Overheat

[ScottEstes]

Last night I was just on the interstate and my 525i (2006) displayed an overheat message - yellow then immediately to red. I was able to hop off at an exit which was a few hundred yards from where the warning was posted. I turned the car off and restarted and everything had cleared. System check said all was well. I drove the car back to the house, the long way, and did not experience another problem.

Details - recently I had replaced a failed hose from thermostat. I had drained the coolant and re-filled with Genuine BMW coolant. Once that was done I ran the process to bleed the air and everything seemed normal. A couple of days back I decided to run the process to bleed the air again. Doing so I inserted a funnel with some premixed coolant. Once completed the reservoir was completely filled and I replaced my cap until it clicked into place. I didnt drive the car right away as I had a lot of my plate and typically drive another vehicle most days.
One other thing I noticed is that after the hose replacement the electric fan will run full speed and slowdown numerous times when the car is first started.

Thoughts?

[N54Twin]

Originally Posted by ScottEstes

Last night I was just on the interstate and my 525i (2006) displayed an overheat message - yellow then immediately to red. I was able to hop off at an exit which was a few hundred yards from where the warning was posted. I turned the car off and restarted and everything had cleared. System check said all was well. I drove the car back to the house, the long way, and did not experience another problem.

Details - recently I had replaced a failed hose from thermostat. I had drained the coolant and re-filled with Genuine BMW coolant. Once that was done I ran the process to bleed the air and everything seemed normal. A couple of days back I decided to run the process to bleed the air again. Doing so I inserted a funnel with some premixed coolant. Once completed the reservoir was completely filled and I replaced my cap until it clicked into place. I didnt drive the car right away as I had a lot of my plate and typically drive another vehicle most days.
One other thing I noticed is that after the hose replacement the electric fan will run full speed and slowdown numerous times when the car is first started.

Thoughts?

Same happened to me once, Replaced my water pump and thermostat an problem fix.

[ScottEstes]

Replacing the water pump and thermostat would certainly fix the issue, but how can I be sure the problem was either? As I mentioned once stopped and turned off and immediately restarted the engine the code had cleared. If it were over temp then I should have been warned immediately since the brief off and on would not provide time for the engine to cool.

[N54Twin]

Originally Posted by ScottEstes

Replacing the water pump and thermostat would certainly fix the issue, but how can I be sure the problem was either? As I mentioned once stopped and turned off and immediately restarted the engine the code had cleared. If it were over temp then I should have been warned immediately since the brief off and on would not provide time for the engine to cool.

If your fan is running at full speed is trying to keep your engine cool.


I was driving on the highway when my problem started my car went into limp mode, open my hood coolant everywhere but don't know where i came from.

So when i restarted the car everything was fine again, since i lost coolant i drove the the nearest autozone to buy some.

After i replace the water pump and thermo never happen to me again.

[ScottEstes]

My coolant level was the same with nothing showing under the hood. Fan runs/stops/runs when the car is started. I am thinking it may be the sensor.
I havent had the car out for a few days. With the current break from the rain I'll get it out and see if the error recurs.

Thanks

[N54Twin]

Originally Posted by ScottEstes

My coolant level was the same with nothing showing under the hood. Fan runs/stops/runs when the car is started. I am thinking it may be the sensor.
I havent had the car out for a few days. With the current break from the rain I'll get it out and see if the error recurs.

Thanks

Good luck