Hi,

I need to gain the maximum economy from my 300SE. I'm just wondering how many miles I can expect out of a full tank if I drive carefully.
I drive about 40 miles a day, the majority of this mileage is on the highway at a constant speed of about 70-80mph.
In the past I have driven with a rather heavy foot, and I have achieved about 280 miles out of a full tank.


Thanks

At the speed you mention, I get about 18mpg - highway.
Driving at 65mpg, I get 20-21 mpg. 93 octane fuel is used.

The faster you drive, the more it drinks.

Sorry to appear a bit slow, but how many miles is that on a full tank?
I only know the capacity in litres.

Thanks again,

Oliver:

I fill the tank slowly until the pump stops. The trip meter is reset and off I go. I might fill-up again when the gauge gets to 1/2 full or close to empty. Either way, I refill using the same technique, then divide that amt. of fuel(gallons in my case) into the miles traveled.

You mention litres; I suspect you're outside of the U. S.
If your car's trip meter accumulates kilometers vs. miles,
you could use a similar strategy, but divide kilometers
traveled by litres added at fill-up.

Fill-up and drive your usual 70-80mph/kpg/whatever. At the next fill-up, calculate your litres per kilometer. Now drive for a tankful at a reduced speed. Fill-up and recalculate.

Thanks!

I'll check it out, and see what kind of economy I can get.

300SE Fuel Economy
 

We drive a mix of highway and in town. MPG averages between 16-22 depending on whether we run the A/C and % of town vrs road. On the interstate, speed varies from 62-72 depending on the speed limit. 25 gallon tank at an average of 18mpg gives you 450 miles a tank.

450!!??
 

Wow!!

I have been monitoring the fuel consumption on my car for a while now. I have managed to get a maximum of 300 miles off a full tank.
I admit I haven't been driving very sensibly.
I filled up yesterday, reset my trip clock, and I have been driving very carefully. If I can achieve 400 miles I'll be a very happy chappy.
Are there any parts that could be replaced to improve economy? I was thinking the distributor hasn't been changed since the car was built, so maybe this will improve things.
Overall, the car runs very well.
I have a few issues at the moment that need to be addressed though if anybody can help:

1. My brakes are leaking quite seriously. I have to top up the fluid daily, I think I've found the leak, it seems to be one of the lines under the car in the centre. I've booked my car in to get this sorted.

2. My air-conditioning doesn't work. I went to a Mercedes main dealer and they said the unit was none mercedes benz so they couldn't help. Are the units expensive?

Thanks again guys!

re: fuel economy
 

Any A/C work now days is expensive because of the EPA requirements. Get a couple of quotes from different A/C shops and good luck.

A good tune up, plugs, wires, cap/rotor never hurts gas mileage.

don't forget the air filter.

Tire pressure, keep at the recommended level, check often.

slipping transmission? had a fluid/filter change recently?

dragging brakes, do you go through pads more quickly than you would expect?

how does the inside of the tail pipe look. A coating of black soot would indicate running rich. Any number of components in the injection system could cause that.

How about a leak in the fuel system. do you smell gas outside the car after it has sat a few minutes after driving.

Off the top of my head these are a few things to check.

PS. I generally fill up as the needle approaches the top of the red. 450 miles is theoretical, haven't seen if it is attaibable. good Luck

ken Juul
91 300 SE
85 380 SL

My 126 goes as far as 350 miles on 1 full tank.

I think the way its driven would play a large role in determining the fuel efficiency.

There are time (in mad traffic jams and driving),I'd only get 260 miles to a full tank. And I'm on 97 RON.