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Old 08-18-2022, 03:23 PM   #1
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Diesel Bacteria?

Bought a new to me Tiffin 33AA with the Cummings diesel on March 1st and then blew my left shoulder. I've driven it about 300 miles but since surgery can't use arm but was told yesterday that I might have bacteria in my fuel tank.

What can I do? I have an oil change scheduled for late October before I head out to FL. Should I add a fuel additive now and run the engine or leave it alone?

What about the DEF? It has been a long time since I messed with it.

I know there is a lot of information out there but looking for info from fellow Rvers so I can get it all going again.

Thanks is advance
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Old 08-18-2022, 03:45 PM   #2
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Are you having performance issues that lead you to question the fuel condition ?
Was the DEF subject to freezing while the coach has been unused ?

If your up-coming service , includes fuel filters being changed ; add the fuel conditioner now and carry a second set of filters with you on your road trip.
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Old 08-18-2022, 04:04 PM   #3
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It's usually algae, not bacteria. You should purchase a good diesel algae treatment and change your fuel filters often.
Cummins recommends Power Service Bio Kleen and you can purchase it online.
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Old 08-18-2022, 04:09 PM   #4
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Bacteria & algae? When diesel fuel sits for a long period of time (6 months +) in a hot climate algae/microbes will grow in the fuel system. That means fuel tank, fuel lines, fuel pump, fuel filters, and the injectors. It's a stringy kind of stuff that clogs up everything and expensive to clean out of the system. I see you're in southern Illinois and I seriously doubt if that's the case for you since the weather needed to grow the stuff didn't hit Illinois until June and from June until now is not long enough to create the environment needed to the stuff to propagate. There is a wide variety of products on the market that will prevent this from happening and among them is Power Service's "Bio Clean". It is a biocide made to kill and prevent growth during long off cycles in a hot environment. I doubt of you're in any danger, but keep the product in mind if your going to spend a long time in Florida. The stuff's potent and the dosage is 1 ounce per 55 gallons for preventative maintenance.
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Old 08-18-2022, 04:38 PM   #5
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What is the basis for bacteria in the fuel? Water in the fuel? Contaminated sample? Fouled fuel filter(s).

If you do not have any evidence of bacteria (contaminated sample or fouled fuel filter(s), I would add diesel enzyme fuel treatment like Star-tron Star Tron Enzyme Fuel Treatment Diesel Additive, run the diesel, monitor performance and change fuel filter(s) at your next planned service. I doubt DEF is at risk of cantamination. I often store my diesel truck for 6 months without a diesel or DEF issue.
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Old 08-19-2022, 04:37 AM   #6
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Originally Posted by vito.a View Post
It's usually algae, not bacteria. You should purchase a good diesel algae treatment and change your fuel filters often.
Cummins recommends Power Service Bio Kleen and you can purchase it online.

A quick web search on algae vs. bacteria and the same basic response came up on the first two that I read:
The first thing to clear up is that, while we called the problem 'algae', it's not actually algae. Algae is what the average joe calls diesel fuel microbes, probably because they're easy to visualize. But algae is a microscopic plant, and since plants need light to grow, there's no algae in diesel fuel.

Power Service Bio Kleen's own web site:
Bio Kleen Diesel Fuel Biocide kills microbes in diesel fuel. ...
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Old 08-19-2022, 08:05 AM   #7
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The best diesel fuel biocide is It treats more fuel at less cost than any other product I have found. I have used it since day one in my diesel coach and never had a fuel problem.
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Old 08-19-2022, 07:00 PM   #8
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Keeping a diesel fuel tank during storage is almost a must with today's biodiesel, which attracts moisture. A less than full tank is full the rest of the way with moisture-laden air. Normal day/night heating and cooling causes said moisture/humidity to condense and fall to the tank bottom. Heaven knows we here in the midwest have enough humidity. I understand this is not an issue in the desert SW.

It is not heat that causes microbes to grow at the line between moisture and fuel it is the actual interface. Microbes cannot grow without water/moisture, but can grow in 40 and 90 weather.
Algae is not Algae
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