I used liquid moly diesel. Ran it until the engine was at running temp (80+C). Ran the engine at idle mostly but reved it a few times to ~3500 or so.

All I got from a 10-15 minute diesel purge was a slight discoloration. It looks like it might have come from the rubber hoses I used to connect the plastic bottle to the primary filter and the diesel left in the pumping system when I started.

Seems a like a wasted effort.

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84 300SD
85 380SE
83 528e
95 318ic

That should make you happy, it means your fuel system is probably in good condition and all is well. I've had the same results, I even went as far as using two bottles and rigging up a mini fuel tank and gone for a spin around the neighborhood to really purge things, but I've found if everything is in good condition then that is the result.

On the other hand, my old 300SD had some of that Seattle hippie sauce in it (home brew bio, who knows how well it was brewed/filtered?) and the car HEAVED one giant puff of soot onto the ground during a purge that actually stained the driveway for a few months. It was sluggish and having trouble cold starting before the purge, I mean REALLY sluggish, but once I purged it the thing ran great and all cold start issues were resolved. I swear it must have restored about 30hp. It also stayed that way for the 5 years I owned it.

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1995 E300 Diesel
~300k

You don't say why you did the purge.

I see it another way, if I used purge and junk came out I would be in full panic mode.

If your car had no issues and you did it as a preventative, then all is well.

There are two Lubro Moly products available for these purposes. Purge is for minor issues like an idle shake that feels like a dirty injector. Despite the way some folks hype it, I find it generally ok only for very minor issues. Some people do swear by regular use as a maintenance issue, however.

There is also a Lubro Moly diesel fuel system cleaner that is much stronger.

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

Most snake oils simply take your money, but a few have actually worked for me. I wonder if anyone ever noticed a difference from adding STP to a gas car in the many decades it has been sold. Some say that Chevron's Techron actually works and isn't just alcohol (used to be Techralin, or vice-versa).

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

Gunk transmission fix is one that has worked wonders for me.

I would say that if your purge didn't change color your fuel system was pretty clean, I'd be happy about it and move on.

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2004 F150 4.6L -My Daily
2007 Volvo XC70 -Wife's Daily
1998 Ford F150 -Rear ended
1989 J-spec 420SEL -passed onto its new keeper
1982 BMW 733i -fixed and traded for the 420SEL
2003 Volvo V70 5 Speed -scrapped
1997 E290 Turbo Diesel Wagon -traded for above
1992 BMW 525i -traded in
1990 Silver 300TE -hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold

I just installed new Monarch nozzles in a set of injectors I bought off ebay. I'm going to put them in tomorrow. Everybody says to purge the injection system before you install injectors with new nozzles. It really sounds like solid logic to not want new nozzles fouled with the old crap that gets past the secondary filter or that which comes from wear on the pumps.

I've only pulled one injector so far and it popped at between 15 and 1600 psi. The spray was just slightly wider than the new nozzle spray. I'm guessing here, I haven't seen the new nozzles pop in several days. I might pop them for comparison tomorrow. I'm in no hurry.

I did notice some black specks in the old primary filter. I removed it before I did the purge. I guess it's time for a can of Startrek or whatever that anit-fungus/algae stuff is called. I can testify that I put a can of it in a the tank four years ago after noticing the black specks in the primary filter and the black specks didn't reappear until now. I'm not saying it works and I'm not saying it whether it algae or fungus either.

Honestly, I was more worried about the purge harming my lift or injector pump than cleaning or fixing anything. I drink the snake oil and leave my Benz to good oil and clean filters.

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84 300SD
85 380SE
83 528e
95 318ic

I recently did a Diesel Purge treatment on my '87 wagon, had great results. I think I may perform another. In my case, the engine was already hot hot hot when I started, and I think that improves the cleaning action. My chief reason for performing the purge was too much smoke under acceleration. The purge cleaned that up, cold and hot starts are better, and fuel mileage seems to have improved a bit as well.

I'm planning to do another purge soon, this time I'll have two cans, and again do this on a hot engine. I'll start by replacing the big spin-on fuel filter, and filling that with purge during installation, and then burn the remains of the first can plus the second can. If the diesel purge turns black again, I may do a third treatment at some later date

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Your 84 300SD (I'm guessing) should pop at 1950 psig. The injector bodies should have "135 bar" stamped on them. Sounds like your set are for a non-turbo (~1600 psig, I recall). I think it is just the internal spring that varies between them, or maybe just the spring shim. Of course, they will work in a turbo. Indeed, I found that my 1984 had 3 non-turbo injectors, but swapping them didn't make a noticeable change. But you probably have the parts to get the factory pressures.

It would be interesting if someone knew the reason why turbo's got higher pressure injectors. Perhaps they were expected to run at higher rpm and thus need a finer spray for faster combustion.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

Yes, it's the 84 300 SD and my goal was to pop them at 1975 psi. I lapped them all and lapped two again to get the pop pressure to 1975. I know it's a waste of time to do this but I have to do something to keep off the recliner.

I just removed the other four and popped them. They all pop between 16 and 1850 psi. The spray looks exactly like the spray of the Monarch which I just installed in the injectors I just bought.

Perhaps the previous owner was fanatical about changing filters. I know I've changed the secondary in less than 10K for the past six years. I try to catch them on every other 3000K oil and filter change but sometimes I forget so I change the fuel filters with the oil change.

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84 300SD
85 380SE
83 528e
95 318ic

Not my specialty, ... but I would expect that an engine with 160% of the cylinder pressure (assuming ~1.6bar boost) would require a significantly higher fuel pressure to inject in the same time period and produce the same pattern.

I'm pretty sure that there's more to it, but maybe?

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Gone to the dark side

- Jeff

Mercedes only needed one reason to create a specification.

Is it possible to get a reamer in that #5 glow hole without removing the oil filter housing?

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84 300SD
85 380SE
83 528e
95 318ic

I have.

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83 SD

84 CD

I still want to know how to get a GP reamer in the #5 hole on a 617 engine. The oil filter housing it exactly in the way.

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84 300SD
85 380SE
83 528e
95 318ic

A now retired MB Master Mechanic / Shop Manager from the dealer near me once told me that back in the 80's & early 90's he instructed all of his mechanics to put a new canister filter full of diesel purge on every diesel motor in for routine motor service i.e. valve adjustment, oil change, etc.

Called it a "Hot Shot". Says customers would rave how much better their diesels ran even after a simple oil & filter change. The secret he says was the routine hot shot.

Better yet was his thick German accent! LOL

First time I tried it, the car (603) had some 225k on the clock, and it made a big difference. Since then it gets done at fuel filter change intervals i.e. 15k or so and I really don't see any significant change. Probably cause the system stays fairly clean. But I still remember that first clean out...so I still believe

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1986 300SDL 440,xxx

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.