[bikefanatic]

Hi there
I'm having an issue with low coolant temp and low mpg. I already changed both thermostats, car had a full service recently- oil and all filters.
When driving in town it gives me around 29mpg and temp is around 70C, 75C after a bit longer drive (30min). I think I had a max temp of 82C
Any idea where to look? No fault codes except glow plugs and relay and aux pump. Car start badly in the morning - I'm gonna change glow plugs soon.
Did anyone had similar issues? Its 2005 e90 m47n2 diesel engine.

Hi there,
i'm driving the E90 with the same engine. I had also a problem with the coolant temp. My maximum was about 65°C at the highway. So i changed both thermostats. This fixed the problem. When you changed the thermostats did you check at which temperature they open ? Because when I was looking for mine to change, i noticed that there are different.. I thing for the engine it should be 88°C and the other one was opening at 70°C.
As i know the newer diesel engines usally have an addiontial heater to achieve earlier the needed temperature. Maybe it has to be replaced also.

By the way, i have also an issue with my glow plugs right now. All 4 are not working, i think its the glow ECU. I'm gonna change it this weekend. But i don't have a problem with the temperature even when glow plugs are not working. So i don't think changing them will solve your problem (of course it should be done also asap).