I use the additive only for noise reduction. I cannot get comfortable listening to what sounds like ball bearing balls banging around inside the combustion chamber and find the less than $1.00 it costs me, when I am having the problem, well worth it. I don't always use an additive, which means a bottle of RedLine will last me more than several months. The added cost is trivial and the peace of mind is highly valued. For me, it doesn't get any more technically complicated. I spend very little time looking for smoke that normally doesn't exit from my 1998 E300 TurboDiesel, or my 1983 240D, to see if the additive had any effect. It is all about being able to hear the regularity of the Diesel engine noise while driving and know all is well. Jim

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Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

I was never able to see smoke until I chipped the car.

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01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

engine pinging can be caused by many things besides fuel. Is the car running good? Is the engine running hot?

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1986 300SDL, 211K,Dealership serviced its whole life
1991 190E 2.6(120k)
1983 300D(300k)
1977 300D(211k)

Of course. But it makes sense to start with cheap/easy fixes. That's why we recommended a cetane booster or different fuel source. If that doesn't fix it, the owner can proceed from there.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

The absolute best additive I've found to combat the loss of lubricity from the ULSD fuels in my '96 E300 is STANADYNE.

How do you measure lubricity? You can evaluate engine noise, but I don't see how you can measure lubricity, unless you're taking out some fuel system component and measuring the wear scars.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

http://www.johnfjensen.com/Diesel_fuel_additive_test.pdf

Problem was they were simply measuring a wear scar. If they had hooked up a bunch of engines and run some on and some off and given us some indication of what is what, I wouldn't be so dismissive of their "report". All we have is "More is better.".

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01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

Lots of guessing here. I especially like guys that think new filters are the cure for everything.

Ours recently exhibited a significant "knock" at idle and some nailing coming off idle.

The dealership tech immediately suspected fuel injector and there is an electronic test (with printout) for fuel injector performance.

We got a new #2 injector ($750) and all is now well.

Understand that the injector test indicates a range of diagnositics and an injector could be approaching but not at the cutoff point where replacement is required--that is, covered by warranty.

Injectors on these engines are not the simple calibrated holes of earlier days, but rather are sophisticated, complicated electronic devices not necessarily going to last forever. Our #2 made it 38K miles.

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

Yeah its a injector balance test. You measure the fuel pressure with key on engine off then you hook a fuel injector tester to see how much the fuel pressure drops when activated. the one that drops the most is the faulty injector.
you can also see the injector spray pattern. A good injector sprays a conical pattern and a bad just sprays straight and dribbles. A injector could be good electrically but could be bad otherwise.

a bad injector will cause an improper an A/F mixture and cause the engine to ping

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1986 300SDL, 211K,Dealership serviced its whole life
1991 190E 2.6(120k)
1983 300D(300k)
1977 300D(211k)

Glad you got your car fixed. You might want to consider Jim's Fine Car Service as an alternative to the dealer. Mickey owns the place, is a Mercedes factory trained tech, has all of the tool / computers required for your CDI and charges only $82 per hour. I've bought parts from him many, many times.

Scott

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Scott
1982 Mercedes 240D, 4 speed, 275,000
1988 Porsche 944 Turbo S (70,000)
1987 Porsche 911 Coupe 109,000 (sold)
1998 Mercedes E300 TurboDiesel 147,000 (sold)
1985 Mercedes 300D 227,000 (totaled by inattentive driver with no insurance!)
1997 Mercedes E300 Diesel 236,000 (sold)
1995 Ducati 900SS (sold)
1987 VW Jetta GLI 157,000 (sold)
1986 Camaro 125,000 (sold - P.O.S.)
1977 Corvette L82 125,000 (sold)
1965 Pontiac GTO 15,000 restored (sold)