My GFs 98 e300 is running low mpg city. About 21mpg city and she drives very, very conservative. The car doesn't shift over 2500rpm when she drives. The car is supposed to do at least 25 city I thought. it has 260k, no fuel leaks good filters. I maintain the car well. My 99 does 24-25 city..

any ideas?

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

Tires? Alignment? Brakes dragging? 4mpg difference is a small enough gap that it could simply be down to driving habits. Constant throttle vs a hunting throttle can net you 3-4mpg right there. So even though she's driving slow, if she's feathering the throttle, out goes your mpg right there. Torque converter locking up properly? FWIW, I average 23-24mpg in my SDL, I'd expect the W210 to do better.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]

i did a trip in philly a couple weeks back (all city driving) and found my mileage around 23, which i thought was low

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0o==o0

James 4:8

"...let us put aside the blindness of mind of those who can conceive of nothing higher than what is known through the senses"
-Saint Gregory Palamas, ---Discourse on the Holy Transfiguration of Our Lord God and Savior Jesus Christ


Centrally located in North East Central Pa.

yeah as far as I know the trans was replaced a few years back. the alignment is out, I did the toe on it but didn't do caster or camber and I did put two calipers on it cause it sat for awhile before I got it like two years. she goes thru a lot of stop and go on her commute to work. red light to red light and she babies back into the gas and keeps it steady.

23 isn't too bad depends on your throttle.. I remember hearing your car run, it had that little clack to it for a few seconds on startup.. usually when the injectors start leaking and the nozzles are old, they get more clack. might be why you're running little bit lower than my car. my car has had 3 sets of injectors .. how's that gold e320 running?

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

In my experience, this is the wrong way to drive a diesel. This driving style (in my opinion) will lead to carbon deposits in the pre-chambers (and more carbon in the oil = more engine wear). As the carbon builds up, combustion efficiency goes down, fuel consumption gets worse, more carbon builds up because the combustion process is less efficient, and the viscous cycle drags the car down.

If you gave the car an Italian tune-up right now, would it belch smoke as the carbon burns out? If yes, then I am sure that this is part of the problem.

I would say stop the babying and mash that accelerator down whenever possible. Keeping the RPMs so low is probably not helping at all. Diesels are VERY different from gassers, engine efficiency has more to do with load and less to do with throttle position. Not familiar with the electronic transmission, if she can select "3" instead of "D" and force the trans to stay in only 1st, 2nd, and 3rd gear (while in city traffic) then she may see an improvement in mileage. This is counter-intuitive, but worth trying.

How often does the car get an Italian tune-up? I try to get at least one or two every day (once the engine oil is at full operating temperature).

I get 24-25 mpg in city driving, but not all heavy stop and go like what you describe, I've got a couple highway jaunts in my commute with speeds up to 70-75 mph, with opportunities to burn out the carbon. This mileage is in my 124.193 (OM603) that has an injection pump from a 3.5 liter engine, and I haven't yet turned down the fuel so the governor is over fueling my car. In other words, I could probably get 26 or 27 mpg if I tweaked the pump governor a little bit.

Last thought: Does the engine get up to full temperature quickly? If the thermostat is bad and prevents full operating temperature, that can also kill your mileage. I just did this on my 124.193 a couple months ago, and gained about 2 mpg as the carbon has been burning out. Old t-stat was keeping the temperature right at 80 deg C in the cooler weather, new allows temp to stay around 90 deg C, and now my mileage is better.

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

LOL I've done 17mpg in the E300D driving around San Francisco.

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CENSORED due to not family friendly words

worn out injectors? conventional wisdom says they're due for a rebuild every 100k miles or so.

clogged intake manifold? 260k miles of ccv and egr can make for a constricted sludged up intake.

dry wheel bearings? the front bearings in particular seem to need replacing on these cars about every 150k miles. brand new w210 front bearings/hubs come with a tiny blob of grease in them, i always repack them before installing, using only the neon snot colored genuine mb bearing grease, it's excellent.

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1998 E300 turbodiesel

America's Rights and Freedoms Are Not The Enemy!

Use Kreen 500 miles before your next oil change, I did that both in my tank and engine on my OM606. I just can't brag enough about Kreen, the injector knock were gone and the oil (drained) came out like gooey tar.

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06 MB E320 CDI 123k miles
14 Sienna (wife's DD) 36k miles
11 GL350 Bluetec 136k (Sold)
96 E300; 292k+ miles (Donated)
11 Sprinter 22K+ miles (Sold)

that's awful. What did you spend like multiple hours idling in traffic?

cleaned that intake after I did the glow plugs. restored a lot of power. maybe the injectors do leak or something. I put used ones in it. I bought it with misfiring cylinders from lazy injectors. wheel bearings feel tight and wheel slides nice and easy.

keen? that stuff worries me putting in your oil. I'd be afraid it washes stuff away it isn't supposed to. if your car came out gooey and tarry that tells me your car has missed a lot of oil changes

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

Very short trips on steep hills with many intersections along the way over the span of several weeks.

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CENSORED due to not family friendly words

Nope all oil change done around 7.5k usually Rotella Synthetic but the car had almost 300k miles. Your gas mileage would increase too.

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06 MB E320 CDI 123k miles
14 Sienna (wife's DD) 36k miles
11 GL350 Bluetec 136k (Sold)
96 E300; 292k+ miles (Donated)
11 Sprinter 22K+ miles (Sold)

hmmm interesting. I'll have to give it a shot but it scares me. if it's such a strong detergent, Id worry it would wash away bearing surfaces etc. Mobil 1 synthetic cured my noisy lifters on my daily driver.. I had a nice tick when I got the car and 0w40 fixed it after 4k

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

Big problem with oil change chemicals is the oil cooler and associated hardware keeps a percentage in the motor...

Best practice is change oil regularly...

Leave the chemicals on the shelf.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

I've hit 34.5 at 70 with ac on very little stop and go.. it's possible. the car has to be perfect tire pressure, no leaks and rpms. the sticker says 26 city.. I get about 24 regularly around town with over a half a million miles

yeah I'm not touching detergents. if you change oil often with good oil and you shouldn't have goo in your oil.

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

OP mileages sounds about right for a diesel. Very high if your car is a gasser.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.