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Does Diesel Fuel go Bad?

Started by Mergyver, 25 September 2018, 11:25 AM

Mergyver

I am getting close to putting my 1979 300SD on the road. The one issue I am still a bit concerned about is the lack of pick up. I have adjusted the valves, done a diesel purge, put in new filters (air,oil,and fuel). I have replaced fuel lines, fixed leaky injectors, and checked the intake system and turbo.

This brings me to the question; The fuel in the tank may be as much as 8 years old (the inspection sticker on the car dates back to 11/2010). I have put Cetane boost in the tank. Is it possible that the age of the fuel reduces its potentcy which makes starting hard and reduces pick-up? If not is there anything else you suggest I look at?

1974 450SEL
1979 300SD
1989 560SL
2005 E320 CDI Recently deceased

Squiggle Dog

Wow, yes. Diesel starts to go bad after about 6 months, from what I recall.
Stop paying for animal cruelty and slaughter. Go vegan! [url="https://challenge22.com/"]https://challenge22.com/[/url]

1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Heated Seats, 350,000+

ptashek

Yes. Diesel goes off quite bad and quite quickly - especially if it's bio-diesel. As it's a much heavier fraction than gasoline, and contains more solids, it'll separate and stary forming layers of tar-like gunk at the bottom. Then there's various types of bacteria and algae that, literally, eat the stuff making it even worse.
1993 "Pearl Blue" W124 280TE
1988 "Arctic White" W124 200T
1979 "Icon Gold" W116 450SE

Harv

8 year old diesel? Oh god yes.

Drain that junk and start fresh.
1980 300SD
1983 240D
2000 E55 AMG
2002 G500

daantjie

Uncle Kent @ Mercedessource will have a wobbly over this one :o
Daniel
1977 450 SEL 6.9 - Astralsilber

Mergyver

Wow! I am not sure whether to be thankful for the quick overwhelming response or embarrassed at what looks like a pretty dumb question on my part. LOL.


I am sure though that I will start draining the tank tonight!
1974 450SEL
1979 300SD
1989 560SL
2005 E320 CDI Recently deceased

ptashek

1993 "Pearl Blue" W124 280TE
1988 "Arctic White" W124 200T
1979 "Icon Gold" W116 450SE

Mergyver

Just watched the wobbly. My fuel looked like the stuff on the left not the new stuff on the right. Just took out 13 gallons. Now I have to figure out how to recycle.
1974 450SEL
1979 300SD
1989 560SL
2005 E320 CDI Recently deceased

Squiggle Dog

Quote from: Mergyver on 26 September 2018, 01:33 PM
Just watched the wobbly. My fuel looked like the stuff on the left not the new stuff on the right. Just took out 13 gallons. Now I have to figure out how to recycle.

Maybe put it in a parts washer tub to clean car parts? It might be too old for that, though.
Stop paying for animal cruelty and slaughter. Go vegan! [url="https://challenge22.com/"]https://challenge22.com/[/url]

1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Heated Seats, 350,000+

gf

With fuel that old not only do you want to replace or check the fuel but consider a new filter. I know you just replaced it but it could be full of gunk, water and rust from that old fuel rotting in the tank