Ml320CDI and ML420CDI fuel consumption

[mikemike39]

We've just bought a new ML320CDI and, overall, love it.

At motorway speeds - so 80ish mph we are getting somewhere around 28mpg. It has only done 1300 miles and the last full tank was from a second line petrol chain so maybe not the best stuff. I had hoped we might get a little over 30mpg once the engine gets a little loosened...

My question is for those who have ML320CDI and ML420CDI what real world fuel consumption are you getting? I am particularly interested in long journeys -especially continental journeys -where cruising at 80-90mph, probably closer to 90mph for many hours might be the norm - how do these two vehicles perform in these conditions? Of course it is important that the vehilce does not have a roofbox I imagine -at these speeds that would make a big difference!

I wondered whether the ML420CDI being a bigger engine would cruise more fuel efficiently at these speeds, or whether it would still chew up more juice??

best wishes (first post, hope this is in the right place!)

Mike

 

[hawk20]

I had the ML270cdi for 15,000 miles and averaged about 27-29 mpg in mixed motoring. On a run it was possible to get 29/30 mpg but only by avoiding hard acceleration and definitely by keeping the cruising speed down to 70 ish rather than 80 ish.

Recently I had a new ML320cdi for a few weeks. Hard to get 30 mpg I found and on a run if you pressed along it had a marked effect. The truth is they are not a very aerodynamic shape and although that matters little round town, it has a major effect at higher speeds.

Later on I had a 420cdi for a couple of weeks and however I tried I could not beat 24/25 mpg on a run.

I find on most diesels it is possible to get the Mercedes combined figure -but only on a run and even then you need to be gentle and watch the cruising speed. Hard to beat the combined figure. For the ML320cdi Mercedes give a combined figure of 30.1 and for the ML420cdi they give 25.5.

 

[hawk20]

BTW we did 3,000 miles in France and Spain last October and worth noting the relaxed attitude to speeding has clearly gone. Lots of cameras sprouting up and mobile units on most motorways.

 

[A210AMG]

Hello

Have to agree with Hawk we do a europe trip twice a year and people are slowing down and camera poping up. Even on the toll roads, last summer I set the cruise at 85mph and unlike our raods you can leave it on for mile after mile sometimes a full tank..

My ML is a Petrol 350 (3.7 V6) and that did 25-26mpg at these speeds with the very occasional quick blast... It was Full to the brim with 2 adults and a baby.

The ML320Cdi I would like to think it might do 35mpg on a long run with cruise? my dads E320 Cdi estate does over 40mpg easily on the same run.

I think at 70mph you would probably see 35mpg (I would hope) it does make a huge difference in mpg increasing your speed slightly.

Its proabably also going to losen up a little over time I would guess?

 

[jonathan.austen@goodman.c]

I have an ML320CDI with 40,000 miles. About 10,000 miles ago had DMS software upgrade. Fuel consumption now typically 32-33 mpg on a long run with high cruising speeds (80-90). Performance also improved. Seems a win-win solution.

 

[JEZ.S320L]

I have an ML320CDI with 40,000 miles. About 10,000 miles ago had DMS software upgrade. Fuel consumption now typically 32-33 mpg on a long run with high cruising speeds (80-90). Performance also improved. Seems a win-win solution.

Welcome to the Forum.

Please expand on the DMS software upgrade. Sounds interesting.

Thanks

 

[hawk20]

I have an ML320CDI with 40,000 miles. About 10,000 miles ago had DMS software upgrade. Fuel consumption now typically 32-33 mpg on a long run with high cruising speeds (80-90). Performance also improved. Seems a win-win solution.

Make sure you notify your insurance company or insurance can be null and void. Small print either says all mods or it will say all mods that may affect performance. And if you are in the 3 yr guarantee period it can affect the manufacturers warranty.

 

[stumpy]

Make sure you notify your insurance company or insurance can be null and void. Small print either says all mods or it will say all mods that may affect performance. And if you are in the 3 yr guarantee period it can affect the manufacturers warranty.

Good advice. On another forum I use a few guys have DMS'd their diesels which apparently are undetectable by the dealer. However, if the dealer needs to reset the ECUs as part of a service or defect fix, then the new program is lost. He then got it re-installed at a reduced price.

 

[hawk20]

Good advice. On another forum I use a few guys have DMS'd their diesels which apparently are undetectable by the dealer. However, if the dealer needs to reset the ECUs as part of a service or defect fix, then the new program is lost. He then got it re-installed at a reduced price.

Yes. And still plenty of dispute about the claim that dealers cannot detect. Not a risk I would take.

 

[stumpy]

Yes. And still plenty of dispute about the claim that dealers cannot detect. Not a risk I would take.

I wouldn't chance it personally. Another chap was told by his warranty company that any claim that was attributed to damage caused by his mods would not be honoured. Re-mapping must surely put more stain on all the expensive bits. Having said that, is this not how the manufacturers create distinction between different models in the range i.e 280 cdi versus 320 cdi. Are the mechanicals different on those cars or do they just turn the wick up a bit on the 320 and that's the only change.

 

[JEZ.S320L]

I wouldn't chance it personally. Another chap was told by his warranty company that any claim that was attributed to damage caused by his mods would not be honoured. Re-mapping must surely put more stain on all the expensive bits. Having said that, is this not how the manufacturers create distinction between different models in the range i.e 280 cdi versus 320 cdi. Are the mechanicals different on those cars or do they just turn the wick up a bit on the 320 and that's the only change.

If that is so - I want mine to be a ML63 AMG. Where's the ****** wick.!!??