W211 320CDI fuel economy & thermostat

[gtahhh]

Hi

I've read that poor fuel economy for diesel cars can be related to thermostat issues. My car very occasionally gets to 90 degs by most often sits between 60 and 70 degs (nearer 60 it seems but the scale is hard to read precisely). When it was really cold a couple of month ago the urban MPG reading would often drop below 20MPG. On the motorway I have been over 40MPG once but I'm not a steady 65mph man, rather I "keep up with the traffic".

Does this sound like the reason I'm not getting better economy?

-g

 

[Dieselman]

It sounds like it could be one reason.

 

[Dblock]

Sounds like it. I replaced mine on a 270cdi. It would sit at 60 on dual carrigeways and get to 80 around town.

Also check your air filter. Mine was pretty dirty.

 

[gtahhh]

Sounds like it. I replaced mine on a 270cdi. It would sit at 60 on dual carrigeways and get to 80 around town..

Sounds similar to the temps I get. What improvement to fuel economy did you get?

-g

 

[Beardz]

The temp on my 320 sits at just over 80 pretty much all the while, and although I'm certainly no expert after reading posts on this forum it does sound like your temps are low.
I also find fuel economy suffers during colder weather, the short trip to work in winter (like now!) only 25mpg same trip in summer 33mpg

 

[Dblock]

Sounds similar to the temps I get. What improvement to fuel economy did you get?

-g

3mpg-7mpg. So 43mpg on dual carriageway to 50. About 3mpg round town though which Im still happy about