I highly doubt that diesel purge could possibly have ruined your glow plugs. My reasoning is that all a diesel purge does is to substitute a high-solvent fuel in for the regular diesel. It still gets injected into the prechambers in exactly the same way, and the engine runs in the exact same manner as with regular diesel. It is true that the energy in the fuel and the cetane value, etc. would be different, but I do not understand how using an "alternative fuel" would cause mechanical failure of glow plugs. I suspect that perhaps something was bumped or happened that caused the GP issue, and it is NOT related to the actual purge.

I have done purges using BOTH SeaFoam AND Diesel Purge. Both work very well.

I don't believe MMO can be used for a purge, although I have dumped a bunch in both oil and fuel tank on a vehicle that saw a lot of city driving, and it does seem to have helped.... I also did an Italian tune with MMO in both fuel and oil, and after about 4-5 hours of driving high-speed on the freeway (with considerable time at 60MPH with the manual 4-speed of a 240D stuck in 3rd gear), it totally stopped smoking, and gained a lot more power, and ran a lot more quietly.

I followed up with a diesel purge, and then ramped up with biodiesel... B20, then B50, then B75, then B100 over 4-5 tanks. Swapped fuel filters 2 times.

I'm now running B100 all the time, and the 240D loves it.

My 240D runs quietly, and dare I say it - It has very adequate power around town, and even on the freeway. The ONLY place where it is a big of a slowpoke is on uphill grades. Everything else, terrific.

Packman

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83 240D - 4 speed manual - Manilla Beige
189K miles, Tachometer mod, cool wooden shift knob from PeachParts, CocoMats, Original factory paint, manual windows, manual sunroof. Starting to add AudioWrap to this car too!

ATF IS NOT MEANT TO BE "BURNT" in place of DIESEL.
THE additives cause a "White Powder" residue to build up in the Pre-Chambers.

[No, y'all are out of Luck, There. Also... No Re-Burning the White Residue in a Pipe,for Medicinal Purposes]

NO MATTER WHAT YOUR "CHALLENGED" G.G.Grandfather ,who drove for Von Ribbentrop told you!

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'84 300SD sold
124.128

Is the 80a strip fuse in the GP relay cracked? I've seen that fuse supply voltage but not amperage before when damaged.

i will take a close look ...
i also have a new set of fuses sitting at my door step thanks to the amazing crew here at Peach/Pelican


more soon

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'81 300SD ---> '46 IHC Metro (some day)

Unless the fuse finds a way to distribute the current disproportionately to the GP's, the current monitor won't know the difference.

A current monitor won't tell you there's a fuse inside that relay... I agree, actually watching current flow or seeing a GP get hot would be a good test.

No but a micro crack in the fuse or loose screws will definitely show up as a high resistance connection and can cause the volts but no amps under load problem.

Same theory as a bad battery cable connection when trying to start the car.

EE 101 school time
Voltage = Current multiplied by Resistance (V=IR for the EE's out there)
If you pass a high current through a high resistance, you will have a large voltage difference across that resistance, or more commonly known as voltage drop. If this high resistance is in series with your source and load, the voltage drop across this series resistance subtracts from your available source voltage. The voltage drops across the resistances in the circuit are proportional to the resistances (Kirchhoff's Voltage Law for you EE's). The largest resistance gets the most voltage drop.

In other words, with no load, you can measure a perfect 12.xx V dc with the car off on the load side of the strip fuse even if you have a high resistance crack or loose screw on the fuse.
But if you turn the key on and energize the glow plugs, you have now applied a large load to the strip fuse. If there is a bad connection, the voltage gets dropped across this bad connection or crack due to the massive current drawn by the glow plugs and the measured voltage at the glows can approach zero.

This is because your glow plugs are in the single-digit ohm range especially when cold (the resistance goes up as they heat up but that's another story for another day), and the bad fuse connection can be tens or hundreds of ohms especially as it heats up under load. Therefore you can drop 90 to nearly 100 percent of your battery voltage across the bad connection.

Same reason why with a bad battery connection you can turn on the lights or play the radio, but try to hit the starter and you have nothing.

Important safety tip, be sure to disconnect the battery ground cable before trying to replace/tighten this fuse! One slip of the screwdriver and it will go boom!

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

people look at me like i'm nuts when i tell them this. "but my grand-pa used to do it, it must be good!"

i would never burn atf in my diesel. no off the shelf diesel additive is made from atf that i've ever seen. a 7-11 slurpee is bright red... doesn't mean it's made with atf.

About six weeks ago I bought a one owner, 139,500 mile 1985 W123 300D Turbo Diesel, I had a thorough inspection prior to the 1,200 mile drive to Dallas. Replaced the leaking feeder pump and made the trip back in just two days, without problem.

Two days ago, I flooded it trying to start it on a chilly morning. After many efforts, the GP light ceased to come on when I prepared to crank it again. I let it sit for about 30 minutes and tried again. It took a couple very long cranks, but it finally started, slowly, but without the GP indicator coming on. I left it at my repair shop, which is experienced in Benz repairs, especially W123 Diesels. The owner suspects the GP Relay may have been "fried" by the extended cranking. Does this sound reasonable? I will not be surprised if they replace the GPs. Does that also sound reasonable?

No.


Yes. The light failing to illuminate is a fault indication, suggesting that one or more glow plugs has failed.