Temperature issue effecting ECO

Page may contain affiliate links. Please see terms for details.


New Member
May 8, 2021
Lowestoft, UK
Mercedes E350 CDI Coupe
Hi all

I'm a newbie here and recent purchased a E350 CDI 2010. Having a strange issue you might be able to help me with.

When driving after about 30 minutes occasionally the temp gauge will drop down like it can't read it, and coolant fans go on full blast and ECO mode is disabled. I've read some threads on here how the engine should be running around 80-90 degrees, however mine barely touches 50-60 on long runs, and only goes higher driving around town stopping and starting.

Also pulling over and switching off the engine and starting up it goes back to normal again and reads a temperature.

So wondering is this a thermostat issue or perhaps an ECU issue?

Thanks in advance

Last edited:

If it has three bolts holding the housing to the block, it's an awkward barsteward to change, because the least accessible of the three bolts is much longer than the other two, and its removal is obstructed by part of the turbo intake trunking, which has to be removed (and the fuel filter disconnected) to change it.
The intermittent fan running full speed is probably a coms issue though, so do get the car diagnosed. Could be an intermittent connection on the temp sensor, as they will run the fan full speed on thag scenario as well
Thanks for the replies, do anyone know of any good indy mercedes garages in my location NR32?

Users who are viewing this thread

Top Bottom