Diesel purge definitely makes a difference, especially if the system has been neglected. If it has been well maintained, it'll probably help a little but not as much. That was the case on my brother's 300SD but both my 190D and my dad's 240D benefited greatly.


As for Techron, I think it works as well, I once had to pick up a car that had been sitting for a year and a half and the Techron helped the engine run without pinging on the old gas. I also think B12 is great stuff for cleaning out carbon. I went through about 3 bottles of it on my 96 Grand Marquis and bit by bit it stopped smoking as much as that was being sucked through a vacuum line. It didn't do a thing on my 190E but that's probably because the CIS system doesn't cause incredible amounts of carbon buildup. Best thing about B12 is it is cheap. Running these things in the tank once every oil change should help counteract some of the issues with the quality of gas in the US.

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.