1999 W210 E300 Turbodiesel Fuel Economy / Engine Oil

[ticex]

Hi there,

I'm new to the forum but it looks like a great place...think I'll be spending lots of time here!

Anyway, I've ran a search but couldn't find a conclusive answer. I've just had the oil changed in my car for the 2nd time since I bought it and the mechanic put the same Semi-Synthetic 15W-40 Diesel oil (MB 229.1 approved) in as before. The car has done 47000 miles so I'd expect the engine to be in pretty good condition inside.

However, I've been finding the fuel consumption (+/- 30MPG overall average) on this car a little higher than other E300's I've driven before. I'd be very interested to know other drivers fuel consumption figures as I can never get it to do more than 33MPG even on a long steady motorway run! I checked up on the oil spec and some people say 10W-40, others 15W-40 and various other specs. Basically, my question is could the thicker oil be affecting the fuel consumption?

Thanks in advance for any advice.

Best Regards,
Michael

 

[jaymanek]

dieselman has one, so hope he responds, but when i had one, think i was getting around 32ish... I really doubt whether the oil makes a difference... What speed do you call steady?

 

[ticex]

I'm not really a technical expert but I just had a suspicion a thicker oil would make the engine use more fuel. Now I hear you were getting around 32mpg my economy seems about normal. Funnily enough the speed seems to make little difference...if I drive at 70mph it does the same as at 90mph. At the end of the day it is a big, smooth and quite quick car so you have to pay for it somewhere!

 

[230K]

Hi there

Welcome to the forum, I have a 98 300TD estate 180K and was getting around 32 average, although i have recently got it up to 35-37 mpg but i do not know how have made numerous changes at the same time.
1.Increased tyre pressures 33F 38R
2.Got Wheel alignment done by MB
3.Changed Refueling station
4.Mobil 1 TD service incl Air Filter (Although same service 10K ago didnt improve mpg)
5. Changed 225/45/17 Toyo Proxies to Vrestein Ultrac 235/45/17
Driving has remained the same 83miles per day commute steady 65mph on A road and cross through 2 towns.

Make up your own mind but i would say it is combination of all 5 changes that have made the diff.

230K

 

[ticex]

230K - Thanks very much for all the helpful info! I'll give the higher tyre pressures a try as it's not so hard as a DIY.

Interestingly enough the car managed to beat all records last night with a 26mpg average over a whole tank!

 

[mark.t]

e300td

35/37 mpg combined use millers diesel power plus, and i always give it a good blow out once or twice a week 69500 miles , mine was owned by a little old lady before and when i first give it a good run the s**t that came out the back was extreme but after a few good runs + millers none at all and still the same today(touch wood) have noticed better fuel comp since............

 

[Branko]

Did the increase in tyre pressure have any drawbacks in terms of ride comfort etc? My Oct 97 R reg E300TD Est seems to stick at 28 to 30mpg.

 

[ticex]

I still have my suspicions about the oil....I may be mad but I will always have this nagging feeling that the car isn't meant to use 15W-40 semi-synthetic oil!

Branko - the increased tyre pressures do make the town ride a little firmer but I think overall it drives better.

 

[mikemoss]

Have you tried BP Ultimate diesel? I'm a confirmed petrolhead, so can't offer any personal experience other than the fact that my old 300TE flew like a bird on Shell Optimax, stopped pinking when towing a heavy caravan up hills - and returned usefully better fuel consumption.

I think there's a thread on posh petrols/diesel somewhere else around here.

 

[230K]

Did the increase in tyre pressure have any drawbacks in terms of ride comfort etc? My Oct 97 R reg E300TD Est seems to stick at 28 to 30mpg.

Branko

Steering a bit lighter and thumps hard over potholes but on the open road very little diff.
I only increased the pressures for driving on the continent with 6 on board c/w roofbox and luggage and then have not reduced them from coming home.
Car did 30mpg with 470L roofbox on holiday in France cruising at 80, i thought this was good.

230K

 

[Benzowner]

One thing that can alter the fuel comsumption for the better, is to drive with the switch in W mode as this selects a higher gear quicker, especially when travelling at about 30 to 40. In W it will go into top, in S mine stays in 4th. My average fuel comsumption towing my caravan of approx 1350kg is about 25 mpg and town driving about 33 to 34 mpg, with air con on all the time.

 

[DrNick]

My 99 E300 TD est does between 32-35, normally at a steady 75-80 down the motorway. AC seems to make no noticable difference, nor does the speed. I pumped up the tyres and thought it made a difference but in reality it hasn't! It was running cool as well, and changing the thermostat resulted in it running at normal temp but again had no effect on consumption.

I put the lowish (in my opinion!) economy down to the high mileage (400k) and down to stuff generally wearing out, but its good to know that this is about par for the course.

 

[ticex]

Thanks very much for all the helpful replies. I now feel reassured that my fuel economy seems about normal! Thanks guys!

 

[Dieselman]

As you have all said 32-33 is about normal. I've averaged 32.64 since I've owned the car. High 40, low 25. The figures are four years data.

The brand of fuel rarely makes a difference on a diesel as they all have similar cetane ratings. Adding Miller power plus may help to raise the cetane a little, but is really to keep the injectors and pump clean.

The reason why the 300TD doesn't do to well on long journeys is that it's undergeared. Take note, the gearing is the same as a C250TD. Also the top speed is over the maximum power output. If my diff goes I will fit a higher ratio one.

I wouldn't increase the tyre pressures as that can lead to very quick wear on the rears.

Holding back from the car in front and anticipating traffic slowing and accelerating works wonders for fuel economy, but is a bit boring. This is normally followed by a full on flat out charge to get the adrenalin going again anyway.

Dr Nick
Nice to see your old bus is behaving itself. If a diesel starts without smoke then there ain't no wear.

 

[stuart1948]

Just bought a 1999 E300 TD today. Fuel consumption not as good as I expected. 30ish. Just wondered has anyone got expereience with magnetic fuel economisers?
Has anyone run on kerosene as per handbook or similar (only40p litre).
And what is the MAF ?

Thanks Stuart

 

[Parrot of Doom]

Magnetic fuel thingies = total waste of money

MAF = senses airflow into the engine so the ECU can get the fuel mixture right

Check your tyre pressures are correct

Change all your filters (air, oil, fuel) and do an oil change. I use 5W-40 fully synthetic.

On a motorway run at 75mph I get 40mpg no problems

 

[Satch]

The differnce in oil is marginal because the "40" bit in 0W40, 5W40, 15W40 is a measure of the oil thickness at 100C, so it is pretty much the same. If you do a lot of short runs makes some difference which is why car makers tend to specify thinner oils now, so they get a better result on the standard Euro fuel consumption tests. Ford specify a 0W20 for some applications which is really pushing oil technology even with full synthetics.

Magnetic fuel conditioners? If it is a cheap one try it but otherwsie save teh dosh and if your mechanic has not done so, try running some injector cleaner through and see if that makes a difference.

As ever, eliminate the cheap and easy things first!

 

[Dieselman]

As has been mentioned already have a proper 4 wheel alighnment performed but have the rears set the outside of their tollerances. They will still toe in but the fuel economy should improve, but that's nothing compared to the fun factor when cornering, it totally removes the understeer.

The E300TD is undergeared so not much can be done for economy except a ratio change.

 

[DrNick]

I suspect its the brand of tyres that makes the difference. There are webpages that show tests of rolling resistance and 10% difference in fuel economy between brands is not unheard of.
Nothing I did made much difference to my economy - tyre pressures, Millers, speed, working thermostat, broken MAF, but I didn't change the tyre brand!

 

[steve1462]

E 300td mpg

well guys dont know what your all towing! behind you,i have a 1999 w210 300td auto, fuel is £1.19 per ltr at mo, i put £50 at a time in and i have never got less than 400 miles to that £50. averaging over 43 mpg!, i would consider my driving as combined, but i am very very light footed, as sad as it sounds its a game i play with every trip, motor ways get a bit boring at 60-65 mph but i always have a smile!!,