You should have 4 seperate sets of dots on your speedo. A single dot indicating the max speed that should be attained in first gear, a double dot indicating the same for 2nd gear, tripple dots for 3rd and then a single dot for maxiumum speed. At least on every car without a tach, this is what I have observed. Cars with the tach usually leave off the last single dot.

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85 300CD
83 300TD
78 240D (daughter)

But you do not state that higher piston speed = higher wear in a diesel engine. Very low piston speed in a diesel designed for higher RPM is known to be worse than high piston speed.

Midrange power is what these diesels love... 2000 - 4000 RPM. Sure you can go higher once in a while to keep things cleaned out and operating as they should, but it's not territory that should be ventured into on a regular basis, especially in a car with a worn engine. Below 2000 RPM is considered lugging the engine, which in some cases can be worse than running at higher RPM, especially in something like a VW TDI, where lugging can mean the death of a turbocharger. Don't misunderstand, the TDI is a completely different beast from these MB diesels, but lugging is still bad in either case.

MTU can attest to this, where do most boats run their diesels? Close to wide open about 80% full throttle if I remember correctly. Heck I know two boats a 63ft Ocean and a 50ft Bert that the owners only run them at wot! They have two speeds off and wot!

If my 603 was in a boat it would run abour 4k rpm for thousands of hours for years. Diesels like to run and an auto box won't let you over rev the motor, drive them hard and enjoy.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

ahhhhh, such a revelation. thatll help me out a lot in determining if its shifting correctly. never knew that. does your daughters diesel shift kinda hard form 2nd to third? just wondering. thanks!

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Fool kids into thinking your a schoolbus and drive a diesel!
1979 240d automatic, 275k miles

I replaced my speedo and dash dimmer switch yesterday, next is new wheels and tires, followed by a tach! Anybody know if the RPMs are counted from a CPS or the alternator??

Thanks,
RObert

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Cheers,
Robert

Mine only has three sets of dots, and has a tach. It also has an easy-to-bury 85mph speedometer, though, so there's nowhere to put the top speed dot.

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1982 300D, black w/ palomino leather, 203K
2001 E320, champagne, 105K (Mom's)
1999 Dodge Dakota, squeaky & battered, 142K

Her's shifts great. She has that 4cyl and downshift figured out to and can keep with traffic most of the time.

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85 300CD
83 300TD
78 240D (daughter)

I certainly don't approve of the following - Florida captains believe boats have two speeds- fast and faster. Even when backing down. Had to change props more than once for a guy who folded the props over by backing down too fast.

Always thought the injection pumps were the limiting factor on my diesels. In otherwords pump could be damaged by overreving it. Example: My pre-1997 vw block is basically the same as the gas engine that will live to at least 6k.easily but the diesel pump cannot stand that type of speed. I have always watched down shifting carefully with my diesels because of this factor. This is besides the increased wear of increased engine speed. Another thing is when my wifes diesel has say 60k miles the engine seems much tighter than one pushed hard on the highways at 30k miles. She drives very conservatively. Just opinions and observations. Because of the oil cooler and large capacity oil pump we should be able to run at maximum allowable speeds without basically hurting the engines on these old diesels. That was the manufactures intention I think but of course your engine will not last as long as it would at more conservative speeds. Less loading has got to equal less wear. Especially the rotating force vector wear. It probably is a greater than linear function.

The amazing thing about these little German diesels is the sound and performance at higher RPMs-both my Powerstroke and Cummins do very little above 3000 RPM, but the 300D is just starting to wake up at 3K. The MBs and conventional bigger diesels are totally different beasts-my Dodge wil chug around all day long at 1500, but the MB only sees that off idle! I'll never get tired of hearing the 300D cook along at 75-80, sounding like a mobile smoky siren! I also disagree with the "hurting it at high RPM" post-these MBs sound so happy at high RPM it couldn't possibly be bad for them!

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1982 300DT 190K (Diesel Purge + synthetic oil=smoothness at last!!!)
2004 Ford E-350 6.0 L PSD 227K
2006 Dodge Ram 3500 SRW HO Cummins 4X4 48RE 42K (brute force tow vehicle)
2005 Scion xB wife's rolling pop can
1993 GMC Sierra C3500 6.2 142K

If it ain't breaking you ain't tryin' hard enough...

I use the loud pedal as an 'on/off' switch.

Ever heard of the "Italian Tune Up ?"

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[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."

I'm no diesel expert but I must agree that there is something about higher revs and these older MB diesels. When I first bought mine, I drove it many hours at about 100 mph and ever since then it has been a better car. I can't say it likes a good crosswind, though...kind of get pushed around sometimes.