2012 C207 E350 CDI - poor mpg

[HB]

Thank you Stratman. I’ll have to check properly but iirc it runs around 80c most of the time and 90c on motorway. But I’m sure it has varied quite a lot in the few weeks I’ve had it.
Is it a big job to replace?

I reckon this is your issue. My temp runs at just about 90 all the time. I had to replace the thermostat at 70k so, I wouldn’t be surprised if yours is on its way out.

 

[OneForTheRoad]

Cool thank you. I’d rather spend the money on property maintenance. May manually clean the EGR one day.
I’m driving 235/35/18 front and 255/35/18 rear. Front tyres are decent Bridgestone (unsure of model now). Rear are mismatched and will get binned ASAP.
I’ll definitely check thermostat

Those sizes seem wrong ...

 

[Stratman]

I'm afraid I don't know your engine so can't comment on how easy or difficult changing the thermostat is, but it does need changing. Once it gets to operating temperature it should stay pinned there regardless of driving conditions.

 

[tonysmb]

A dirty air filter , still flows and filters even better .

It's all about the Cetane .

That being the case, I'm surprised that the manufacturers haven't removed filter changes from the service schedule .

Of course, once it's absolutely clogged it filters really well; it stops everything, including the air. Other views are available.

 

[Weds]

My 212 350 CDi estate has done 31.7 mpg over 35,000 miles of ownership. On the motorway driving very carefully I can see 40+mpg, but I didn't buy it for that, I'd have bought a 4 pot if I did.

 

[OneForTheRoad]

My 212 350 CDi estate has done 31.7 mpg over 35,000 miles of ownership. On the motorway driving very carefully I can see 40+mpg, but I didn't buy it for that, I'd have bought a 4 pot if I did.

The 7g box was never good for anything above 40mpg tbh. Even the 9g don't see much more. I said this before as you kindly mention. If your gonna twist about road tax and fuel costs, buy a fiat 500.

 

[OneForTheRoad]

I'm afraid I don't know your engine so can't comment on how easy or difficult changing the thermostat is, but it does need changing. Once it gets to operating temperature it should stay pinned there regardless of driving conditions.

Om642. The one with the 6 inch bolt .

 

[Tanny100]

So did a little test this evening. Drove 5 miles from cold and the temp rose to 60 then shortly after to 80c. Carried on driving and after around 30 mins it finally reached 90c. I think that is too long and indicates a thermostat problem.

Once at 90c it didn’t drop. But yeh I took what seemed like an age to get there

 

[Tanny100]

The 7g box was never good for anything above 40mpg tbh. Even the 9g don't see much more. I said this before as you kindly mention. If your gonna twist about road tax and fuel costs, buy a fiat 500.

I’m happy with 40mpg. My other cars are an Audi Q5 3.0 Quattro which is lucky to go over 30mpg and an EP3 Civic Type R with shorter final drive and gets mid 20’s

 

[Tanny100]

I’m sure someone up your way will recommend someone buddy , where in sunny Lancs are you ?

I’m in Accrington near Blackburn (cannot wait to move)

 

[tonysmb]

Reasonable figures are available from these cars; the two below are from a south-north trip through France (normally do 3 or 4 per year, but not recently ), on the Autoroute at the speed limit, so 80, 70 mph, or lower on the peripheriques/ring-roads, including stops, traffic queues/static on the ring-roads. Stop/start deacivated but if it's clearly going to be a stop of more than 5 minutes I'll probably switch off.

Car was the C207 265 version, 7g+ and these were taken a few years ago. I'm not that bothered by the car's actual consumption but at one stop I was flicking through various screens and saw it, so also looked later on. Accepting that these readouts aren't necessarily 100% accurate, the amount required to refill the tank, with rough mental calculations, wasn't far off. Having another car that would probably average 13mpg under similar conditions and not be any quicker overall, I was quite impressed.

I don't drive to save fuel and don't hang around but do try to anticipate ahead, reducing the number of brake/accelerate situations and obviously traffic conditions, in the main, were favourable once clear of the cities.

 

[Tanny100]

Reasonable figures are available from these cars; the two below are from a south-north trip through France (normally do 3 or 4 per year, but not recently ), on the Autoroute at the speed limit, so 80, 70 mph, or lower on the peripheriques/ring-roads, including stops, traffic queues/static on the ring-roads. Stop/start deacivated but if it's clearly going to be a stop of more than 5 minutes I'll probably switch off.

Car was the C207 265 version, 7g+ and these were taken a few years ago. I'm not that bothered by the car's actual consumption but at one stop I was flicking through various screens and saw it, so also looked later on. Accepting that these readouts aren't necessarily 100% accurate, the amount required to refill the tank, with rough mental calculations, wasn't far off. Having another car that would probably average 13mpg under similar conditions and not be any quicker overall, I was quite impressed.

I don't drive to save fuel and don't hang around but do try to anticipate ahead, reducing the number of brake/accelerate situations and obviously traffic conditions, in the main, were favourable once clear of the cities.

View attachment 113596View attachment 113597

Hi Tony. That’s frankly amazing consumption for a 3.0 diesel. As I say economy isn’t number 1 when I buy a car bit of course it’s always welcome.

I’m going to get my thermostat changed and get some new tyres and I’m sure that should get it running efficiently.

Thanks for sharing your

 

[HB]

Hi Tony. That’s frankly amazing consumption for a 3.0 diesel. As I say economy isn’t number 1 when I buy a car bit of course it’s always welcome.

I’m going to get my thermostat changed and get some new tyres and I’m sure that should get it running efficiently.

Thanks for sharing your

Buy the original thermostat if you can . If memory serves me , it was around £150 supplied and fitted by my Indy.

 

[Tanny100]

Buy the original thermostat if you can . If memory serves me , it was around £150 supplied and fitted by my Indy.

Thanks HB. I need to find a Merc Indy in Lancashire.

 

[Benz17]

Hi my W213 in London gives me around 29mpg, if it lots of stop/starts then around 18mpg, on the motorway between 80-85 then I get around 39mpg, if steady 70 I get around 44mpg, if my recollection is correct, didn’t buy the 350d for steady 70mph

 

[Tanny100]

Hi my W213 in London gives me around 29mpg, if it lots of stop/starts then around 18mpg, on the motorway between 80-85 then I get around 39mpg, if steady 70 I get around 44mpg, if my recollection is correct, didn’t buy the 350d for steady 70mph

Haha! This sounds similar to mine then but I only get over 40mpg on hour plus steady motorway drives. Anything else and it’s in the 30’s.

My car takes ages to get up to temp though

 

[OneForTheRoad]

World shortage of om642 thermostats right now . Hopefully you can find a dealer part.

Mine takes about 10 miles to get upto 90 ...

 

[Benz17]

Haha! This sounds similar to mine then but I only get over 40mpg on hour plus steady motorway drives. Anything else and it’s in the 30’s.

My car takes ages to get up to temp though

Mine is 9g gearbox so that may make a difference on getting better mpg on the motorway.

 

[Tanny100]

World shortage of om642 thermostats right now . Hopefully you can find a dealer part.

Mine takes about 10 miles to get upto 90 ...

Sounds like mine! Is there really a shortage?

 

[OneForTheRoad]

Sounds like mine! Is there really a shortage?

There was a week ago. My e350 has only done 16k so I'd assume the thermostat to still be pretty accurate, but at 7 miles to work its getting towards 80. 3 more miles id say would see 90 . Time taken around 10 to 15 minutes from cold.

I average 38 mpg all the time tbh . Thats work and back 7 miles each way. I might get a long run in one day .