I know that gas goes sour after sitting for awhile but does diesel ?

In the vehicle ... in a sealed system

It will grow algae especially in a marine environment but it stays viable as far as combustion is concerned for a looong time.

I have a truck that has been parked for 15 years that the fuel looks positively nasty, dark brown bordering on black but it will fire right up. Series 60 Detroit Diesel.

Kevin

Thx Sears guy from Roebuck

Marine same/same as higher humidity situations?

So will the filter out the algae? Or is that not a worry ?

A bud has a Cat d and I have a Cummins in a motorhome...

Algae is actually a misnomer for what is actually happening. It's apparently a bacterial thing that grows on any water that might be in the fuel. It's more of a problem on a large boat because they tend to carry hundreds of gallons of fuel and with large fuel capacity comes large potential for water contamination.

http://www.boatcoachbob.com/articles-boat-maintenance/engines-inboard/prevent-remove-diesel-algae/


It shouldn't be an issue on a motorhome that is properly maintained and gets a few tanks of fuel run through it regularly. A fuel/water separator filter ahead of the main fuel filter is pretty standard these days on automotive diesels and should eliminate any water that might find its way into your fuel tank. No water, bacteria can't grow.

Kevin

I ran into the problem by getting a tank of contaminated fuel in my 2010 Cummins. A dead giveaway is changing the fuel filter and finding it blacker than the ace of spades. Only thing to do then is get some bacteria killer and add it to the fuel tank. I was told the Cat stuff was the best and that's what I used. Took care of the problem

Will it fire through that bacteria?

But Sears guy .... NEITHER of our motorhomes have been used much in the past couple of years .... I maybe have a HALF TANK in my older Airstream.... but that’s over FIFTY GALLONS! ... what to do ??!!

Pull a sample and see how it looks. Like I said with mine, the fuel is 14 years old and it looks nasty but it fires right up. Don't know how long it would run at speed before the filters plugged up. I don't know if the fuel is dark from bacteria or it's just dark because.

50 gallons isn't a lot of fuel and as long as there isn't a bunch of water in it, you shouldn't have a bacteria issue.

Kevin

...... because ..... of age too ? .... have you ever tried that algae treatment? And it can be that bad that it will plug up that filter ?

Never changed one myself ... is it best under these conditions to keep a spare filter on board and be prepared to change on the road if it needs it. Canister filter on most ? Should you bring a separate can of fuel to prime the system after the filter change ?

I haven't checked my fuel for algae as it's been parked for 14 years. I just noticed when I moved it last summer that the fuel was very dark. Could just be from age. If it is bacteria causing the colour change it would eventually clog the filter.

I haven't used the additive because it's just not an issue in an automotive application, especially when you burn 100 gallons or more a day and use quality fuel.

Is yours a 12 valve or a 24 valve? 24 valve engines all use an electric lift pump to move fuel from the tank so you could just keep cycling the key to prime the fuel system after a filter change. 12 valve had an engine driven transfer pump as far as I know, at least on Dodge trucks, so you would need a jug of fuel to fill the filter with. No reason you couldn't do the same with a 24 valve to speed up the process.

Kevin

One of my friends who is a professional truck driver always has a spare set of fuel filters for his semi. He got caught once with a tank of bad fuel in Wherethehellarewe and limped about 50 miles to the next town that had filters.

On my '93 a few thousand miles after I bought it I swapped out the filter. Bright green pond scum looking algae when I poured it out onto the white cardboard filter box. As a former fuel hauler I did see a 1000gl tank at Marathon Bordeaux in Nashville labeled "algaecide." Allegedly biodiesel will clean all of the trash out of your tank/lines and dump it into the filters if you have been running straight diesel.

Tell me about it. The first time I came across the stuff was in Texas and I think it was posted on the pump "up to 20%" 3 sets of filters in less than 100 miles on an N14 Cummins and the first 2 plugged up so bad it wouldn't even idle. After the 3rd set it was good, never an issue again.

Good solvent that soybean oil...

Kevin

When the dually was running fuel mileage on B20 was 17.8, straight diesel was 21+