My first Trip - PeachParts Mercedes-Benz Forum

79300sdtd · #1 03-09-2006, 12:45 AM

In my 300SD. It was from denver to aspen and back in one day. I averaged 70 mphish and got 28.25 mpg. 8 hours of driving in total.

I am thinking that 28 mpg is not that great. In the car, it was me, 5 sets of twin sheets, my masasge table (32lbs), tire chains, a bit of diesel additive, 2 lucas oil products, jumper cables, and a few other light things. as far as i know the alda has not been adjusted.

also When i got off the highway the oil pressure gauge was vibrating, it would only stop vibrating when i would shut the car down then restart it.

any suggestions on how to improve the mileage and why the oil gauge was doing what it was. Oh i did a diesel purge, changed the oil, and filters (air, oil, fuel (primary, and inline)

other than thoes few little things it was all smooth sailing.

thanks

Ara T. · #2 03-09-2006, 12:49 AM

The mpg you are getting is great especially since you were going 70 mph.

pawoSD · #3 03-09-2006, 01:50 AM

My oil gauge does that from time to time when I go to idle after driving for a while, most often when I am in the city, a quick tap on the throttle makes it go away, though if I wait it usually does on its own.

28mpg is good! I usually only get about 24-26 on the freeway tops, since I do about 75-80 (people in michigan are speed demons, and there's no cops anymore, so they go all the faster)

By sunday I will have driven about 1,000 miles this week.

Lycoming-8 · #4 03-10-2006, 12:24 AM

That fuel mileage was pretty good as the previous posts indicated, but take the same trip this summer and you should get better mileage. The winter diesel, particularly in the colder regions of the country, will have less energy per pound and deliver poorer mileage.

JimmyL · #5 03-10-2006, 01:21 AM

Ahh, you're in a near 4000lb car going 70mph and got a little over 28mpg???
Umm, I think I would be estatically happy over that one! Very nice...

rg2098 · #6 03-10-2006, 07:01 AM

How accurate is your speedometer / odometer? It is very possible they are off causing your mpg number to be off for the good or bad. 28 sounds a little too good for a W126. The 1985 model year OM617 powered vehicles are rated at 22 / 25 city/highway. I got 26 in my lighter W123 doing 65-70 on a 4 hour trip.

http://www.fueleconomy.gov/feg/findacar.htm

willrev · #7 03-10-2006, 07:34 AM

I have a 1982 300sd and I have never gotten that kind of mileage going 70MPH. I can only get 28-29 when I keep the car at 55mph on a road trip.

I can get 25 mpg in town. I am going to have my injectors cleaned and rebuilt and balanced in hopes it will increase some. I did my valve adjustment recently and mine jumped 5mpg just by doing that.

I drive with a heavy foot too.

doppx006 · #8 03-10-2006, 10:00 AM

28 is good for these cars but when you think about other vehicles it is not that good. If I baby mine on a sweet summer day my 76 300D might do that if I say please. I also have a 2004 Dodge ram 2500 with the Cummins Diesel, this vehicle weighed 6700 lbs from the factory with no options, if I travel at 70 mph winter or summer I will usually range from 18-21 mpg if I am unloaded. I am comparing 2 different beasts here but for a 7K lb truck that is not very aerodynamic to get 18-21 at 70 is alot more efficient than a car weighing 4k at 70 mpg getting 28 mpg. Than I think about semis and I start to feel sick, because a semi maxed out at GCVW is around 80K and they will get 6-9 most of the time. Think about the efficiency there with that weight and aerodynamic drag, shouldnt my truck weighing around 1/4 the semi (my gcvw is around 21K) both at gcvw and my truck having at least 1/3 less aero drag wind resistance I now get around 6 mpg if I operate at gcvw shouldnt my truck get 24 mpg + if they ran at the same efficiency ? Food for thought.