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Valve adjustment may help if they're way out, also check timing chain stretch, adjust via offset keys if needed. Check IP timing too, that will affect MPG, set to the advanced side of spec (maybe 1° advanced from spec). I forget what diff ratio that car has but I bet it's 3.07 or lower (higher numerically, maybe 3.27?)... if so, taller gears will help (2.87 or thereabouts). Don't mess with tires, that will screw up the speedo & odo. Just keep pressure to ~35 or so to reduce rolling resistance. New filters is a given, ditto with making sure the brakes don't drag (wheel should spin freely). Stick with the usual 15W-40 diesel oil, or 5W-40, I'd use synthetic if it doesn't burn much.
The diesel fuel available where you live can affect MPG significantly. Many states now only get the enviro-friendly diesel fuel, which has lower BTU content than the old stuff. There is NO way to tell from the pump labels. Most all of CA, NV, ID, WA, and parts of OR get the crappy fuel. Most of Utah still had the good stuff as of last year. Easy to tell as my cars get 10% better mileage with the good fuel, and it drops the same amount when refilled with the junk. Every time. No other changes. VERY annoying. Idaho had the good stuff until around 2005 or so, then the junk got phased in, now there's nowhere in the Boise area with good #2 diesel.
Anyway - low 20's is not great, that car should be mid-20's, or upper 20's on good fuel. But the 617 engine is an old design and not particularly efficient. I would seriously consider trading up to at least a 617 turbo (which gets better mpg, despite that seeming illogical), or better yet a 124/201 chassis with OM60x engine. That can push you into the 30-35mpg range, or near 40mpg with a 190D 5-speed.
Is that just Boise area or all around? I'm pretty sure Ada county is the only one with emissions testing. They could be giving you the leftovers from OR and WA as well, I know both of those use oxygenated fuels.
AFAIK, it's everywhere in the Treasure Valley, for several years now. I haven't found any diesel fuel in Caldwell / Nampa / Meridian / Boise that's equivalent to what I was getting in Utah last fall.
Canyon County started emissions testing in 2010, btw. Had to get my cars smogged for the first time. The gasser test isn't bad, haven't taken the diesel there yet... that could be a problem as it's, um, modified and smokes more than normal when you blip the throttle off idle (no smoke under boost though).
Great responses and advice that came in after I checked it last.
Much appreciated.
I was seriously ill for a while and couldn't keep up.
I am well now again.
Thanks again to all, I will try to implement the advice given !!
well not trying to brag but, I came across a Mercedes Benz 300SD for 250.00.
it was a co-worker of mine that was in a tight pinch.
and the production model number blew me away #126 as I don't know how many exactly were made.
also, it just need's TLC
the motor was never tuned and the turbo had major build up, seats are all cracked dry so the stiching is breaking apart and the paint is severly faded, any recommendations to what i can do first besides using diesel seafoam and carbon cleaners.. and yes i have a saggy driver seat it makes my back hurt.
On the surface I was impressed, getting the 000126th car of the (of all) W126 line in a Mercedes.
Yes , to me also in the top ten best cars of Mercedes models ever made,
BUT
I am glad you posted the VIN tag.
AND I hate to burst your bubble, but
You have car number 168067 th car in this line (they were built from 81 to 85 with this engine).
The model being (W)126.)
I haven't checked the production numbers , but you may have one of the LAST w126 with the indestructible 3liter I5 diesel motor.
04-14-2011, 10:21 PM
