E350d Terrible mpg SOLVED

[Daddyoftwo]

Your disbelief has caused a baby unicorn to die, shame on you.

If you want to disbelief me and think that I am somehow connected to TerraClean then so be it. All I can say is that I clearly have a Merc with an e350d dashboard which does mpg in the mid 50s at 12.45pm (which was when I read people's disbelief in my post and took it for a spin as I said I would at about 12.15pm).

My main point is to check thermostats. Why don't you think that I work for a thermostat company?

 

[geoffus]

No idea. I just know that on my Jag a couple of days afterwards after Terracleaning, I had to make a 200 journey, it was pretty icy and a lot of 60mph average speed but I got over 70mpg and looking at it the next morning I had a flattish tyre. That was amazing for a 2.2d heavy estate. It had done about 140k. Then the economy went down to getting about 50mpg on a run which for was still superb. Over the next 55k / 4 years of ownership it went down to getting about low 40s mpg which was still good for a car with nearly 200k on the clock.

TerraClean suggest cleaning every 15000 miles. I thought that was a bit of a sales thing to get it done more than necessary. But maybe I'll spend the £130 every two years.

Can you tell what the Terraclean does? Was it for fuel lines and injectors or did you have the carbon cleaned ?

 

[Flash]

If you want to disbelief me and think that I am somehow connected to TerraClean then so be it. All I can say is that I clearly have a Merc with an e350d dashboard which does mpg in the mid 50s at 12.45pm (which was when I read people's disbelief in my post and took it for a spin as I said I would at about 12.15pm).

My main point is to check thermostats. Why don't you think that I work for a thermostat company?

You have made your point

 

[Gazwould]

I'm just put off by the name .

 

[Flash]

Electrical connection on a thermostat is a new one on me (but lots of stuff is )

On the OM642 engine the thermostat does have a electrical plug connection.

 

[Gollom]

Not sure why people seem to be ganging up on a new member? He observed something and shared it (which surely is what this forum is all about) If you choose not to believe/buy-in to it then fine, but why the derision. And I have been around this forum as an active user long enough to know that it didn't use to happen this much. Just saying!

 

[OneForTheRoad]

I'm just put off by the name .


View attachment 109293

Zelda . Motherof2

 

[Daddyoftwo]

It was the standard TerraClean £130 for over 3 litres. The guy didn't let me have the cheaper £110 price when I said the engine is 2.99 litres : ).

They run it off a special fuel to clean out the fuel lines and injectors and they claim the combustion chamber. Then they have I believe a different fuel with cleaners for post combustion ie egr, turbo.

I had asked the mechanic to look at the egr as I suspected a problem there as on my Jag it was terrible - had to replace twice before blanking off. But he said to me that it was okay but he had blown some soot off of it.

There are more expensive TerraClean options.

I don't know what effect it has had on this car as both that and the thermostat were done at the same time. Also I suspect that despite many motor manufacturers saying that these products aren't needed if the car is properly maintained, running it too long at colder than optimal possibly for a couple of years would have led to increased carbon deposits. And anyway the car has done coming up to 90k miles and diesels build up carbon.

From what I've read if the injectors are on the way out Terracleaning may push them over the edge. Otherwise it's pretty safe

 

[Flash]

Not sure why people seem to be ganging up on a new member? He observed something and shared it (which surely is what this forum is all about) If you choose not to believe/buy-in to it then fine, but why the derision. And I have been around this forum as an active user long enough to know that it didn't use to happen this much. Just saying!

I 100% agree with you!

 

[Daddyoftwo]

Not sure why people seem to be ganging up on a new member? He observed something and shared it (which surely is what this forum is all about) If you choose not to believe/buy-in to it then fine, but why the derision. And I have been around this forum as an active user long enough to know that it didn't use to happen this much. Just saying!

Thank you

 

[geoffus]

It was the standard TerraClean £130 for over 3 litres. The guy didn't let me have the cheaper £110 price when I said the engine is 2.99 litres : ).

They run it off a special fuel to clean out the fuel lines and injectors and they claim the combustion chamber. Then they have I believe a different fuel with cleaners for post combustion ie egr, turbo.

I had asked the mechanic to look at the egr as I suspected a problem there as on my Jag it was terrible - had to replace twice before blanking off. But he said to me that it was okay but he had blown some soot off of it.

There are more expensive TerraClean options.

I don't know what effect it has had on this car as both that and the thermostat were done at the same time. Also I suspect that despite many motor manufacturers saying that these products aren't needed if the car is properly maintained, running it too long at colder than optimal possibly for a couple of years would have led to increased carbon deposits. And anyway the car has done coming up to 90k miles and diesels build up carbon.

From what I've read if the injectors are on the way out Terracleaning may push them over the edge. Otherwise it's pretty safe

In a previous life I had a BMW320d at 98000 miles the EGR valve and EGR cooler were completely bunged up with carbon.
When I stripped it down the carbon was hard as nails, took a long time to scrape it off using EGR cleaner and a scraper, if Terraclean can do the same it’s outstanding. Not saying it didn’t but they must use some scary chemicals.
Funny enough didn’t make any notable difference to mpg.

 

[OneForTheRoad]

In a previous life I had a BMW320d at 98000 miles the EGR valve and EGR cooler were completely bunged up with carbon.
When I stripped it down the carbon was hard as nails, took a long time to scrape it off using EGR cleaner and a scraper, if Terraclean can do the same it’s outstanding. Not saying it didn’t but they must use some scary chemicals.
Funny enough didn’t make any notable difference to mpg.

Your joking !!!!

 

[Daddyoftwo]

Your jok

Your joking !!!!

In a previous life I had a BMW320d at 98000 miles the EGR valve and EGR cooler were completely bunged up with carbon.
When I stripped it down the carbon was hard as nails, took a long time to scrape it off using EGR cleaner and a scraper, if Terraclean can do the same it’s outstanding. Not saying it didn’t but they must use some scary chemicals.
Funny enough didn’t make any notable difference to mpg.

.

TerraClean offer a special EGR cleaning service for more money, but the guy said that my Merc EGR was okay and I think that he had just run an air line on it for free.

On my Jag I did try cleaning the old EGR once. It was really difficult - like your BMW - and it still didn't work afterwards (there were two types and this was the electronically controlled version). I note that there aren't as many EGR complaints on Merc Forums as for X Type jags. Had a 330d BMW cabriolet before the Jag - but I don't think that it had an EGR

 

[OneForTheRoad]

In a previous life I had a BMW320d at 98000 miles the EGR valve and EGR cooler were completely bunged up with carbon.
When I stripped it down the carbon was hard as nails, took a long time to scrape it off using EGR cleaner and a scraper, if Terraclean can do the same it’s outstanding. Not saying it didn’t but they must use some scary chemicals.
Funny enough didn’t make any notable difference to mpg.

The Mrs cleaned our gas oven last week with Mr.muscle . We now get 16 Yorkshire puddings to the kilowatt.

 

[Phil1968]

Not disagreeing that your MPG has increased due to the new thermostat but a true average fuel consumption figure is from a cold start. My van will do an average 50 mpg if I reset the MPG readout driving at a constant 70 mph with the engine warm. 35 if I don't (as that takes into account the cold start & town driving until I get on the motorway).

 

[W1ghty]

Just saying check your thermostats if you get terrible economy - especially as mine didn't throw up any engine lights, or error codes in my £20 eBay OBD2 reader. And temperature on guage looked reasonable.
... and if that was the problem, then you might need to use something like TerraClean to get the cruddie carbon out.

Good to know about the electrical connection in the om642 buddy , mine is 12 years old now so it’s probably overdue but still reads correctly so I’ll hang it out .

 

[geoffus]

The Mrs cleaned our gas oven last week with Mr.muscle . We now get 16 Yorkshire puddings to the kilowatt.

How many strikes can you get before you get banned, asking for a friend.

 

[Daddyoftwo]

Not disagreeing that your MPG has increased due to the new thermostat but a true average fuel consumption figure is from a cold start. My van will do an average 50 mpg if I reset the MPG readout driving at a constant 70 mph with the engine warm. 35 if I don't (as that takes into account the cold start & town driving until I get on the motorway).

Hi Phil

Of course you're right. But say if I was doing a 200 mile journey then the start would be pretty irrelevant. Also on a cold Feb day the initial economy will be worse than say Aug in the South of France. So, I'm trying to look at like with like by comparing the mpg to when I previously hit the reset on the motorway when the engine was already heated up. This presumably is closer to how manufacturers calculate the "extra urban" mpg figure. I could only get about high 30s at best before. Before the economy was terrible - now it seems to be up there with the best of what people are getting on their E350d's and the people who claim that they are actually very economical for a 3.0 litre diesel. I also realise that the on board mpg display is likely to be pretty inaccurate and I should use brim tank of fuel to brim tank.

But at the moment I'm like a dog with two tails as the one feature which I really hated about this car, which otherwise I like a lot, has changed to be a strength. It's gone from a drunkard to a fully fledged member of Alcoholics Anonymous. And I wonder how many other Merc owners have cars with dodgy thermostats given that they don't really throw up many warning signs other than high mpg.

 

[geoffus]

Had a drive to the farm shop in the next town today, this was the actual mileage from cold in town and B roads.
This was also driving like Miss Daisy.

 

[Gazwould]

The 250 short journey , benchmark...




From cold , to town , to village .