My '82 300D turbo has been running great. Today I bought diesel fuel at a new (for me) location called Ultramar. Now the car clanks like a cold diesel engine at idle even when at operating temp. The tank is still full. It's been 10k miles since I changed the pre and main fuel filter and 7k since the valve adjustment. Any suggestions about what i should do and if I should wait till the tank is burnt off first. I'm due for an oil change (3K).

I have a few cans of diesel purge which i have yet to use.

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1972 450SL
1982 300D Turbo

I personally would get under it and drain the tank into jerry cans. They may have mixed gasoline in it or it may have a LOT of water. No sense in letting it ruin your engine.

You can also try the typical additives; PS Diesel Kleen, PS Diesel Fuel Supplement, etc.

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1984 300D Turbo - 4-speed manual conversion, mid-level resto

1983 300D - parts car

1979 300TD Auto - Parts car.

1985 300D Auto - Wrecked/Parts.


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"If you don't know where you are going, any road will get you there". Lewis Carrol

Tom,

Thanks for your response. I dread the idea of draining 21 gallons of diesel. I'm not really set up for this. The car idles hot like it's still cold. Is there really damage possible? The car runs OK at higher speed with some loss of power. I guess draining is the safe way but it could be a total coincidence that someting else ran afoul when i filled up. I'm not sure which additive to use since I'm not sure what the problem is. If there is water I may need one additive and if it's high octane contamination maybe i need a different additive. I'm going to drive back to the filling station today to ask them if they've discovered a problem or had other complaints with this pump. I'll start throwing in additives too.

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1972 450SL
1982 300D Turbo

Erubin,

Try Power Service "Diesel Kleen" first. Even though the DFS is "supposed" to deal better with water and winterizing issues, my experiments have shown me that, of the two, DK actually does a better all-around job of cleaning, removing water and winterizing. It will also increase cetane.

One thing you might try that's an easy fix right now, is replace the plastic pre-filter. It's inline, easy to get to and replace. The fuel might have a "winterizing" additive that can kill algae and clean the tank and you might be dumping some "goo" out.

Easy try and most engines need the filters replaced anyway. For $2-3, it's good preventative maint and may help solve a running issue right now, especially if there's some high-speed power loss.

Good luck!

__________________
1984 300D Turbo - 4-speed manual conversion, mid-level resto

1983 300D - parts car

1979 300TD Auto - Parts car.

1985 300D Auto - Wrecked/Parts.


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"If you don't know where you are going, any road will get you there". Lewis Carrol

I use an old Volvo ele. fuel pump with about five feet of hose on both inlet and outlet to get fuel out of my SD to put in my 240D as I rarely take it to town. I have long wires on the pump that clamp on the battery it takes all the pain out of taking fuel out...........
William Rogers.......

TomJ,

"most engines need the filters replaced anyway".

There's a no brainer if I ever heard one. If the engine runs OK at full throttle with no loss of power, it doesn't need the fuel filters changed.

So if we did the above test on 100 cars, how many would not pass the test? If it was not over 90%, it certainly would not be "MOST".

P E H

Erubin,

I'd run it as is until almost out of fuel and see if filling with the fuel you previous used made any difference. Let us know if different fuel does makes any difference. You might take off the fuel line and drain a little fuel to see if it has water in it. You can do this without spilling much if you jack up the car or put it on a lift or back the rear end over a drop off. The water will be in the bottom of the tank and come out first.

I have never seen any type of Diesel fuel I used make any difference in running in any of my Diesels. I have used, kersosene, 2 cycle gas/oil mix, fuel oil, vegetable oil mix, used crankcase oil mix etc. Diesels are a multi fuel engines and run on almost any type of liquid fuel.

I've been running Diesels for 35 years so I have a lot of experience.

P E H

I went back to the gas station and discovered I had actually filled 16 gallons of gas in the 300D. I sure felt like an idiot. I drained all 20+ gallons, changed the main and pre fuel filters. Blew out the line w/ compressed air and loaded up 5 gallons of diesel before I drove it to the diesel pump.

After draining and refilling I now know my fuel tank capacity and determined i was running with 80% gas and 20% diesel. It was real hard to start the car the three times I parked it but incredibly it did run. I actually drove it 20 miles this way. I sure hope I didn't damage anything.

Full power, easy starting and relatively quiet idling have returned. My main concern now is that it doesn't start burning motor oil. I wonder if the cylinder walls got scored by gasoline washing them clean instead of being lubed by the diesel. The oil level did not change after the 20 miles so maybe the gas didn't do too much harm to my 200k mile engine.

This has been a very humbling experience.

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1972 450SL
1982 300D Turbo

erubin,

My Father-in-law did this a little while back and the consensus here and by the mechanic he took the car to was it did no damage. In fact, it may have cleaned things out a little. He drove about 50 miles or more, then drove to the shop he uses and had them drain the system, change the filters and refill with Diesel. He is in his mid 80's now and so he rarely does much on the car himself. Overall I think his ego was damaged more than anything in the car. These machines are pretty stout. Good luck, 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)

Here's erubin's statement from above:



He also stated it's been 10k miles since a filter change. Hence my conclusion that it could use a new filter, regardless of anything else.

BTW, EVERY (not "most") MB I've EVER pulled parts off of at junkyards had black filters that look orig or at least 5 years old. This is a different crowd, MOST owners of older MB's do NOT change their fuel filters when they should. That's where "most" comes in.

__________________
1984 300D Turbo - 4-speed manual conversion, mid-level resto

1983 300D - parts car

1979 300TD Auto - Parts car.

1985 300D Auto - Wrecked/Parts.


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"If you don't know where you are going, any road will get you there". Lewis Carrol

You are to be commended for your honesty. The members of this forum are looking for answers to car problems that they can relate to. A lesser person might not have a follow up to this posting. I don't think you have harmed your engine.

TomJ,

My contention is that if there is no loss of power when the engine is under full load, there is no need to replace the fuel filters no matter how long they have been in use. Fuel filters actually filter better when they start to plug up, removing smaller and smaller particles up until the point they will not pass the molecules of fuel. At that point not enough fuel will pass thru the filter to supply the fuel the engine's need at full power, although it will run OK at lower power levels and start OK.

Fuel filters plug up proportiional the dirt or algae in the fuel used, not to mileage. Therefore a mileage standard of replacement times is illogical.

The primary filter in my one 300SD has been there since I got it five years and 50,000+ miles ago and is going to stay there until I notice some loss of power. The secondary would be there also if it hadn't got a hole in the can and started to leak fuel.

"Most owners of MB Diesels do not change their filters when they should" is because they are smart and know that fuel filters need to be replaced only as required as shown in the above test, not because they look dirty.

NOTE: filters can also be cleaned and reused. MB used to have a special tool to clean the fuel filter cartridge that went inside the old style permanent fuel filter. At today's labor rates, it wouldn't be practical, but if you do it yourself it is.

P E H

"Fuel filters actually filter better when they start to plug up, removing smaller and smaller particles up until the point they will not pass the molecules of fuel. "

Right on

There are spare filters, proper size open end wrench and rubber gloves in the trunks of my cars. My daughter called from the city a couple months ago describing the symptoms of a plugged fuel filter. She had no trouble dealing with it and didnt even get her hands dirty. I remember once having a vacuum gauge in the wheel house of a tug to monitor the condition of the fuel filters. (vac monitered between the filters and engine) When the needle got into the red, time to change filters.

Steve

I would never go 50,000 miles between filter changes. You're asking for fuel problems (clogged injectors etc.). Too much potential for too many problems. The filters are cheap too, they're worth doing. No one will ever fault you for changing any type of filter too often.

Tod

"You're asking for fuel problems"

Of course it wouldn't hurt to change filters, every 30K like the book says but a clogged filter would not harm the injectors as nothing is getting past the filters. The last time I had to change filters I was on a road trip and noticed when on a long pull, a slight loss of power. That coulda happened just after getting fuel that was bad or 50K down the road, either way its not gona hurt anything. There is usually lots of warning time, maybe not enough to find a parts store, so you better have what you need in the trunk
Steve