2012 C207 E350 CDI - poor mpg

[E55BOF]

The thermostats usually fail open to some degree. If the car gets up to 90 eventually, and stays there regardless, the 'stat may be on its way out, but hasn't failed yet. If the stat has an electrical connector in the housing, it's over £160 to buy, and an indie will charge about an hour's labour to fit it.

 

[Tanny100]

The thermostats usually fail open to some degree. If the car gets up to 90 eventually, and stays there regardless, the 'stat may be on its way out, but hasn't failed yet. If the stat has an electrical connector in the housing, it's over £160 to buy, and an indie will charge about an hour's labour to fit it.

Thanks for the above. I will buy one ASAP and either fit it myself or have an Independent garage do it.

 

[Tanny100]

Update:

Just bought a genuine MB thermostat. Will install myself as soon as it arrives. Also thinking of renewing all discs and pads as the car doesn’t stop in a hurry. There is a small lip around all the discs.

Also parking brake isn’t the best. Hoping it can be improved with just an adjustment.

Only had the car a few weeks but already having to spend a bit of money on it. It’s ok though - it’ll run like a dream after this and should serve me well for a few years.

 

[E55BOF]

Update:

Just bought a genuine MB thermostat. Will install myself as soon as it arrives. Also thinking of renewing all discs and pads as the car doesn’t stop in a hurry. There is a small lip around all the discs.

Also parking brake isn’t the best. Hoping it can be improved with just an adjustment.

Only had the car a few weeks but already having to spend a bit of money on it. It’s ok though - it’ll run like a dream after this and should serve me well for a few years.

If it's the same as my 2013 CLS, you'll need to remove part of the turbo trunking, and I think at least loosen the fuel filter, to remove the extra-long bolt holding the housing on (the one most difficult to reach). Depending on the condition of the various seals involved, you might feel it wise to replace some or all of them too.

Doing it yourself, if you can raise the front of the car a little you won't need to drain out any coolant apart from syphoning out the header tank; the thermostat housing will have no coolant in it.

 

[Tanny100]

If it's the same as my 2013 CLS, you'll need to remove part of the turbo trunking, and I think at least loosen the fuel filter, to remove the extra-long bolt holding the housing on (the one most difficult to reach). Depending on the condition of the various seals involved, you might feel it wise to replace some or all of them too.

Doing it yourself, if you can raise the front of the car a little you won't need to drain out any coolant apart from syphoning out the header tank; the thermostat housing will have no coolant in it.

UPDATE

Had the thermostat fitted end of May and the car now gets up to temp and stays there. Happy days! MPG improved significantly. Thanks all for your help.

 

[OneForTheRoad]

Yesterday's trip to cleethorpes over the humber bridge. 9g , mixture of 70 , 40 , 30 mph . Was upto 46.6 at 1 point .

 

[Tanny100]

Yesterday's trip to cleethorpes over the humber bridge. 9g , mixture of 70 , 40 , 30 mph . Was upto 46.6 at 1 point .

Great MPG

 

[Tanny100]

To give an idea on my results after the thermostat change the the best I saw on a steady 70mph cruise on a 150 mile drive was 52mpg! But that was probably aided by the recent map too - which is now being taken off due to causing issues

 

[HB]

To give an idea on my results after the thermostat change the the best I saw on a steady 70mph cruise on a 150 mile drive was 52mpg! But that was probably aided by the recent map too - which is now being taken off due to causing issues

Good idea removing the map. Sometimes you get real cowboys mapping cars although I don’t know who did yours. You pay a bit more but quality people like MSL and DMS are worth it.

 

[Tanny100]

I got it remapped by Superchips who I thought were a reputable company and expected amazing service. I now know they’ve been taken over by another company and perhaps do not have the same ambition and service as the former firm

 

[EthanPrince]

Save your money on the carbon clean buddy , it might dislodge some hunk of gunk that then clogs something else up downstream .
As above check your thermostat temp .
What size tyres and pressures are you running ?

Hi all. So as some may have seen already I’m a new member on here and love the 2013 pre-facelift E350 coupe I’ve bought but one thing that’s bugging me is I’m not getting nearly the same MPG as some owners are on here.

Around town I get about 17mpg max and on a 30 mile motorway journey between 50-70mph I get 44mpg max. On both occasions I was in Eco mode and driving gently.

I’ve read one thread on here about perhaps getting my thermostat replaced. The same chap also had a carbon clean done. What do you guys think?

The car is on 68k miles and full MB service history.

Thanks

Hi all. So as some may have seen already I’m a new member on here and love the 2013 pre-facelift E350 coupe I’ve bought but one thing that’s bugging me is I’m not getting nearly the same MPG as some owners are on here.

Around town I get about 17mpg max and on a 30 mile motorway journey between 50-70mph I get 44mpg max. On both occasions I was in Eco mode and driving gently.

I’ve read one thread on here about perhaps getting my thermostat replaced. The same chap also had a carbon clean done. What do you guys think?

The car is on 68k miles and full MB service history.

Thanks

Hi Tanny,
I have just bought a 2012 E350 CDI (Coupe) with 66k miles. I’m getting the same mpg values as you had! 17 around town and mid 30s on longer trips. Did you figure out exactly what was wrong?
Thermostat or air filter?
I’m running 255/35/19s on the rear could this play a part in the very low mpg!
Thanks
Ethan

 

[OneForTheRoad]

Hi Tanny,
I have just bought a 2012 E350 CDI (Coupe) with 66k miles. I’m getting the same mpg values as you had! 17 around town and mid 30s on longer trips. Did you figure out exactly what was wrong?
Thermostat or air filter?
I’m running 255/35/19s on the rear could this play a part in the very low mpg!
Thanks
Ethan

Should be 255 30 19.

My 17 reg sees 48 mpg on a run. 31 to 39 AVG mpg

 

[EthanPrince]

Should be 255 30 19.

My 17 reg sees 48 mpg on a run. 31 to 39 AVG mpgS

Should be 255 30 19.

My 17 reg sees 48 mpg on a run. 31 to 39 AVG mpg

Sorry my bad, 255 30 19 rear and 235 35 19 front.
Rear tyres need replacing very soon. Just read ahead and saw that the MB thermostat replacement and new tyres did the trick.