'99 E300 turbodiesel
 

Replaced copper seals and o-rings on delivery valves as forwardmost one was leaking. Thanks for whoever asked the question about removing the intake manifold -- about an hour after I too was stuck -- that 10mm bolt which was aligned to be difficult and the #5 allen key accessed from beneath the car were key pieces of info.

Mileage isn't that good. 22 to 23 around town. Car says 77K on odo but according to MB network when it was last serviced it had 180K and that was in 2005. Car is very clean inside and out. What do I do for the mileage improvement?

I do blow black smoke on kickdown (and it does deter anyone in the rearview) and am thinking new injectors but have been told it's too soon. Besides, they're tough to find and MB wants 183 per.

I've read a lot of threads and seems like a DP, diesel purge, (I'm getting the alpha soup down some) might help. Guess I'm taking the lazy way out and just putting Diesel Clean by Power Service in tank. New air and fuel filters and some new fuel lines with the viton o-rings also installed.

Everyone's been really helpful (especially with no service manual at hand and the alldata ain't so great). Any concise listing of posts or whatever to improve the mpg?

Doubtful there is any reason to replace your injectors with 77k (or 180k) on them. They are probably fine as they are or you have complaints such as nailing. You could have the spray patterns checked, have them pop tested and reblanced (if needed) if you are really concerned about them. Mine have never been out of my engine.

I've never driven an entire tankfull around town so have no knowledge of city mileage. I typically get 31mpg on D2 (27-28 on B99) driving 110 miles a day, 80% of which is at 80mph and 20% at 5-20mph.

I'd look for other fuel leaks and then do a DP as it is a) cheap, b) may help and c) wont hurt. Heres a video how if you havent seen it yet. http://www.peachparts.com/shopforum/showthread.php?t=113596

Thanks, Terry. Seems as though this last tank of diesel (Hess stuff which is 2.79/gal 1/4mile south of local MB dealer) is giving me 25mpg. No leaks at all from car. Did read online that takes a month (sounds like a long time) for all the air to get out of fuel system. I did hit the throttle a few times and blew black smoke which doesn't seem to happen anymore -- still blows exhaust but more like a bus and not as black. perhaps the mpg is just a function of stop and go traffic which is terrible in the Tampa Bay area.

Rags,

My '98 is giving me about 25-26 combined hwy/cty and about 30 on the road. I think it could do better but there's some things I need to fix before I get too critical.

Yours is probably about 1-2 MPG below normal for a '98 - so you may still have some crud to blow out of it. The '99s were rated a little higher for highway MPG, I have heard it was due to some fine tuning in the cam and/or tranny but don't know for sure, I just know the EPA ratings for the '99 are a couple of MPGs higher than for the '98.

turbodiesel mpg...
 

Have been using Diesel Kleen here in Florida and am trying to max out mpg. Had a 240D in the eighties which got a steady 28mpg around town and 36 highway. Thought I'd get at least 26-28 around town with this straight six diesel but still only 23 to 24. Is it the right foot penalty or what?

No leaks, additives moderately, get black exhaust at end of gear wind-up when I do use wot, use cruise (@77mph on highways and 50 to 55 locally), any ideas or is this good. Was looking forward to 32+mpg on open road and haven't seen it yet. Thanks, Rick

My E300 typically gets 23-26mph. The is a country drive of eight miles to town and a lot of small town driving. This is the car my wife drives and she drives it Very inefficiently. I can always get more or of it.

I have also learned that the state of running AC is more efficient that open windows is not always true. I April I took this car on a 600 mile trip. The first half of the trip I ran the AC an got on 29mpg. On the return trip I shut off the AC and opened the moon roof and two windows part way. I got 35mpg.

The absolute most I've had from mine is 500 miles on a full tank - those are British miles, I'm not sure if they're the same as US miles.

I can squeeze 23 plus gallons into my tank, and when I did that I registered 717 miles to the tank. But I routinely get 30 mpg on the highway, maybe a bit more now and then, coupled with around the town driving. I would love to see 35 mpg, but never have. Jim

How's the car's performance? Could you have a brake caliper dragging? Sometimes the parking brakes can stick if they haven't been used for a long time and someone new starts driving the car and using it. That could trim some MPG off too...

I have posted this many times before but it could just be that you need to drive a good long while with some strong pedal to clean it out. When I first got my '98 I got the same mileage as you do but after the first year it started to creep up to the high 20s and now I get 27-32 routinely. It takes quite a lot of spirited driving to clean these out.

Did you clean out the intakes into the head and manifold? That could be part of the mileage issue. So can the leaks. Also, what about the plastic lines?

You can take the injectors out to be tested. You see, I had 1 dirty injector at 120K so if you had 180K then, I would say it is time to have the injectors checked and possibly cleaned. Cost me $70 to test all 6 and have one cleaned and retested. That will tell you the condition of your injectors instead of the DP crap where you take a SWAG at the condition of your injectors and possibly enjoy the placebo effect.

THink I'd check the accuracy of the odometer.

Good point, Terry...make sure you have the stock wheel/tire size on there (215/55/16)...if not you could have speedo/odo error that may account for the lower MPG.