Ok guys, WHAT IS THIS STUFF, for real? Yes I've read the tech sheet, but WOW! I have 3 Mercedes Benz diesels, all of the 602/603 engine family in various stages of life. I noticed immediately a noise and smoke reduction in all three, but here's the wow, for no better way to put it. The engine in the best mechanical condition went nearly silent of diesel knock or snap, and totally smoke free on the first tank. It now runs nearly equally as quiet as my gas cars. This is especially noticeable at startup. What I don't believe and am still amazed by is the worst one, a 1987 190D Turbo with 273,000 miles. I just drove it to L.A. from Chicago with a major detour through Colorado and Utah on single lane high altitude roads. This along with averaging 80mph on most interstate highways. I knew this engine to be the least well cared for (I bought it used 50,000 miles ago) and was exhibiting exhaust valve seat and guide wear issues, along with poor smokey starts and poor cold weather warm up as well. This was after replacing injectors, distribution valves, filters, timing, bad glow plugs, etc., etc., etc. I was down to a valve job and a pump overhaul lastly. I know it still could use the valve work, but now, not anytime too soon. At idle, there was always a distinct unburned fuel or rich "burn" stench present in the exhaust as well as a "soft" pulse in the exhaust from the weak cylinder. Well, after 2,800 very hard driven miles and constant use of Star TronŽ, I kid you not, this engine now runs as smooth as a 5-cylinder could possible run AND, the rich smell is gone, the smoke is gone, the snap is gone. It starts with out missing. I can still feel a very slight "miss" or weak cylinder at idle, but nothing like it was before the Star TronŽ treatment over the 2,800 miles to L.A.. I would have loved to have borescoped and photographed the intakes, combustion and pre-chambers and exhaust passages in the head before and after the trip to asses the changes So, fill me in on what happened! And what or where can I expect a peaking of improvement, i.e., the number of miles or hours where maximum benefit is realized? As I mentioned, I'm closing in on 3,000 miles of usage so far with the 190D.
        - Thanks, Mark Gallagher