[SB_Paul]

New member and happy new 2011 N55 E90 owner here.

Taking our first long road trip after recent purchase, slogging through stop and go downtown Los Angeles freeway traffic at ~midnight, my 2011 335i N55 Sedan with Manual Tranny and 45K miles threw a yellow Coolant/Temp error light and then immediately turned to Red error and dropped into limp mode. Coolant temperature gauge showed nominal, no change.

I managed to get car over to the curb lane and upon shutdown and restart the error light had cleared so I drove to service station and did inspection and determined that no coolant was leaking as far as I could tell. Continued drive another 45 minutes on highway before repeat of quick yellow then red and then limping. Again temp gauge remained at nominal. Second shutdown/reboot cleared things up long enough to get home.

Additional Info:
1- Error lights have remained clear for past week of driving around town since event and found no ECU codes using my OBDII scanner

2- Expansion tank level was right at Min/Low indicator tab (I've got newer yellow stepped indicator in tank, not the older style float) and accepted no more than 250 ml of coolant to get to Max level.

3- Advice from local BMW dealer SA is that I was probably just a bit low on coolant, just fill it up that's it, no worries.

4- Advice from my Indy shop is that water pump is likely getting ready to fail. (former owner had not replaced pump or thermostat)


Questions:

a) Has anyone experienced a Red Coolant error light and limp mode due to being low ONLY 1/4 Liter of coolant without any prior warning?

b) Is there likely a failed thermostat or water pump in my near future?

c) Assuming no leaks, how much coolant (and how often) do you think I should need to add fluid in my N55? I live in moderate climate (almost never over 90degrees F here and usual summer highs here are under 75F ) and I don't rev/drive the car too hard.


Thanks in advance!
Paul

- 2006 325i MT with 140,000 & 2011 335i MT with 45,000

[opjose]

Originally Posted by SB_Paul

New member and happy new 2011 N55 E90 owner here.

Taking our first long road trip after recent purchase, slogging through stop and go downtown Los Angeles freeway traffic at ~midnight, my 2011 335i N55 Sedan with Manual Tranny and 45K miles threw a yellow Coolant/Temp error light and then immediately turned to Red error and dropped into limp mode. Coolant temperature gauge showed nominal, no change.

I managed to get car over to the curb lane and upon shutdown and restart the error light had cleared so I drove to service station and did inspection and determined that no coolant was leaking as far as I could tell. Continued drive another 45 minutes on highway before repeat of quick yellow then red and then limping. Again temp gauge remained at nominal. Second shutdown/reboot cleared things up long enough to get home.

Additional Info:
1- Error lights have remained clear for past week of driving around town since event and found no ECU codes using my OBDII scanner

2- Expansion tank level was right at Min/Low indicator tab (I've got newer yellow stepped indicator in tank, not the older style float) and accepted no more than 250 ml of coolant to get to Max level.

3- Advice from local BMW dealer SA is that I was probably just a bit low on coolant, just fill it up that's it, no worries.

4- Advice from my Indy shop is that water pump is likely getting ready to fail. (former owner had not replaced pump or thermostat)


Questions:

a) Has anyone experienced a Red Coolant error light and limp mode due to being low ONLY 1/4 Liter of coolant without any prior warning?

b) Is there likely a failed thermostat or water pump in my near future?

c) Assuming no leaks, how much coolant (and how often) do you think I should need to add fluid in my N55? I live in moderate climate (almost never over 90degrees F here and usual summer highs here are under 75F ) and I don't rev/drive the car too hard.


Thanks in advance!
Paul

- 2006 325i MT with 140,000 & 2011 335i MT with 45,000

My N55 E90 of the same vintage will throw a coolant low error long before it goes into limp mode if it is actually low on fluid.

My car did something similar to yours however about a week before my water pump died.

I had no other errors before the pump left me stranded in the middle of the night w/48k miles on the car.

[bimmerlove335]

Sounds like the typical signs of a failing water pump!