Thermostat

[carbob]

Thanks for all the input, but I may have misinterpreted some of the information I have been reading, and I don’t want anyone reading this to get the wrong impression, so I’ll try to correct myself here, please let me know if I still don’t have it right. Higher engine temps and cooler, dense air provide for better combustion, better mileage and better emissions. So BMW engineers added a higher set point thermostat, but recognized that higher temp means more risk of engine damage, that is the balance they are trying to achieve. The information shows that thermostat opens at engine outlet temp of 110C without DME control information. But the added functionality of the MAP allows the thermostat to open at lower temps if there is a need for better combustion- as in high RPM’s; and it fully opens the thermostat at 113C outlet temp regardless of any other parameters. So the engine is allowed to run a little hotter but mitigated from running too hot. This is a good thing overall, but adds some complexity and maintenance- they always seem to go hand in hand. I hope that helps.

I did replace the water cooled thermostat……but immediately on starting the engine the battery icon stayed lit on the dash. With the engine running there is 11.8v which looks like no charging and a new alternator is needed. If interested see new thread “Another Alternator”.