I am planning a trip for thanksgiving to tucson from las vegas and Im unsure whether to take the f250 diesel that gets 18mpg highway at best or my W124 that i am unsure of mpg due to non functioning odometer....ok, my question is does anyone with the same platform have confirmed mpg with om603 at 75- 80 mph highway mostly flat....if it matters me my wife and two children inside....any insight would be appreciated..
thanks

Arlo

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W211 E550
HVAC/R Certified Technician

I have an '87 300D-T sedan. My mileage driving around 60-65 MPH has been a pretty steady 30 MPG. I don't know about 75-80, but I would think it would cost you a couple of MPG.

I, too, have a F-250/18-20 MPG, so I know what you mean.

You will certainly enjoy the trip much better in the Merc. Drive it.

I have a 1986 300sdl. It is the w126 with the 603 motor. At a steady 70mph on flat interstate with no A/C on my best mpg is 29.5.
Throw some hills in there, turn on the A/C and I am a consistent 25-26 mpg.

My car is larger than yours, I believe the w124 gets a mile or two per gallon better than the w126.

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John
1986 300sdl
1985 380se

At 75-80 loaded you probably won't get 30, I'd bank on 28. You might get better if all is good; alignment/brakes/tires/IP seals, etc.

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Gone to the dark side

- Jeff

Thanks for the quick responses i just need to convince the wifey that the 1987 mercedes benz can beat the comforts and reliability of her 2004 F250 she does not pay for the fuel....

Arlo

__________________

W211 E550
HVAC/R Certified Technician

Hi Arlo,

I've been logging my last 3 tanks, but mind you as you know, I am still tuning this thing and running it hard to test out the shift points, accelerator point, etc. My 1st two tanks was 24. My last tank was 25.5 mpg. This is going around 65-75 mph on the freeways about 50 miles round trip and then about 10 miles local driving each day (Total 60 miles). I think I can do better

On winter diesel, expect 25 - 26. Summer fuel 27-28.

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1959 Gravely LI, 1963 Gravely L8, 1973 Gravely C12
1982 380SL
1978 450 SEL 6.9 euro restoration at 63% and climbing
1987 300 D
2005 CDI European Delivery
2006 CDI Handed down to daughter
2007 GL CDI. Wifes

I just filled up today and got 30, which was about 85% hwy miles. It was with at least 50% winter diesel (the other half didn't say whether it was or not, but I assume so) This was 65-70 mph though.
This is with my boost sensor working, which I think helps.
I also have leaking delivery valves, although I don't know how much that would actually affect the mpg.

Before winter diesel and with no boost + 1 girlfriend I was getting around 30 as well. I would imagine now I could probably pull off 32 with non-winter fuel.

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Dan
2005 E320 CDI - 246k
1987 300SDL TD05-16g, Herlevi pump, Elbe manifold, 2.47 LSD - 213k
Past: 1987 300D - 264k

Thanks again for all your responses, we decided to take the 300D so i gave it some pre trip TLC fuel filterts air filter etc....im gonna try to log gas mileage from map quest directions.. (tells you how many miles to each town or highway change) wish me luck it is a 21 year old car...

Arlo

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W211 E550
HVAC/R Certified Technician

arlo,

have a safe trip. funny weather out west these past few days