dark grey diesel fuel and no glowplug light. - PeachParts Mercedes-Benz Forum

rickjordan · #1 07-16-2001, 01:00 AM

I am working on my father's '85 300D for the week and I need some help. For starters when I look down at his pre-filter, the color of the fuel is literally dark grey, almost black. The car won't accelerate to save it's life, you have floor it to get it moving. Compared to my car you would think his engine was a non-turbo 4 cyl. The other problem is his glowplug light will not come on. I checked the bulb and it's fine, he does have a couple bad glowplugs, but the light should still at least come on and flash after the engine has started. At least that's the way my car is. I only have the car until Saturday. My father traveled up from VA on his way to MA to visit his father. Since the work he needs done was going to take more than a day, I let him take my car to MA. For his black diesel fuel, I would like to just put in some fresh diesel, but his take is only half empty. I would have to do alot of driving in 4 days to get rid of that garbage in the tank. Unless someone might know what causes diesel to be that color. Right now the battery is out of the car. His battery tray was covered in acid corrosion, which I have since given a baking soda bath to get rid of. I repainted the tray and will be putting it back in today. Once I have the battery back in I will turn the key and see if the glowplug relay is working. Thanks

rickjordan · #2 07-16-2001, 10:16 AM

Well, I changed his filters but haven't had a chance to drive the car yet. I think his big problem was his choice of diesel. I poured out the fuel that was in the main filter and it was a very dark grey with small particles of something in it. The pre filter was the same. I am figuring the main filter was clogged up. I will have to ask him where he gets his diesel and is he their only customer. I had his battery out to clean up his battery tray, got it back in but didn't check to see if I can hear the glowplug relay come on or not. I work the car by day and work aircraft at night. I'll tackle it some more tomorrow.

unkl300d · #3 07-16-2001, 10:38 AM

Might be a good idea to drain the
gas tank and maybe blow air through the gas tank filter.
Maybe you have algae in tank?
Good luck.

rickjordan · #4 07-16-2001, 12:39 PM

You know I was thinking that maybe that's what I am seeing. The problem is one, I have never drained a tank before and second, what do I do with 10 gals (half tank) of diesel? I don't even have enough jugs to hold 10 gals.

longston · #5 07-16-2001, 02:25 PM

I suggest that you see if you can drain some fuel from the bottom of the tank to see how much water you get before you hit diesel. The black stuff is likely to be an algae. After you remove all of the water, you can buy a cheap electric fuel pump and some clear plastic in-line fuel filters. Attach a filter, then pump from the fuel line back into the tank until the filter looks nasty, then change filters untill it looks better. Go to a major boat shop, and buy a biocide or algaecide to kill the lifeform, add it to the tank, along with an additive that is used for boats that burn diesel when they are put in extended storage. It should disperse all of the remaining moisture, and may even treat the contamination.

Burn up the diesel, and when the reserve light comes on, you should be able to remove the filter in the tank. Clean, or replace it, along with the primary and secondary fuel filters (if you didn't already) and refuel, adding some more aglaecide, along with some Redline Diesel Fuel Catalyst, 85+, or a diesel fuel conditioner from a boat store, or even Stanadyne additives from a local diesel injector and pump repair shop. I would be shocked if it didn't run a lot better.

For more information, do a search on http://www.google.com for contaminated diesel, algaecide for diesel fuel, etc...

As for the glow plug light, mine didn't light until I replaced the defective plugs. It works fine now.