H2O in Fuel

[jkoeni01]

I have a Cummins 330 diesel powering my 2005 Newmar Kountry Star. On our trip returning from a rainy weekend in Illinois and with very damp weather my engine reported H2O in Fuel. I stopped, drained a total of three cups of fuel from the fuel filter to no avail. The drainings took place over three separate stops where the warning would go out and then come back on again. Finally, I added winter fuel additive to prevent moisture. Please let me know your thoughts regarding my actions and what I should do in the future. My Spartan manual suggests I also have the engine checked which I plan to do. The check engine light never came on while driving. Thanks for any help anyone can provide.

JimK

2005 KSDP 3910

3rd year RV rookie

Toad: 2003 Subaru Legacy

[garykd]

Hi JimK,

Congratulations on your good taste in choosing a coach. You did exactly what I would have done. With a 100 gallon fuel tank, it will take quite a bit of the moisture removal additive to get to the concentration needed. Look on the product and determine how much you need.

I would:

1. Add the correct additive and fill the tank with fuel.

2. Drain some additional cups out of the fuel water separator.

3. Take the coach out for a 50 mile test run.

4. If no problems occur, fill the tank again.

5. Keep the fuel tank really full when the coach will be parked for any amount of time (over a week).

[wolfe10]

Let's back up a minute.

Tell us what you got when you opened the primary filter/ water separator. Draining into a glass jar is best, as you can see what you have.

Was it all golden yellow (clear clean diesel)?

Was there a separate layer BELOW the golden yellow diesel-- could be clear if pure water or any color of muddy water if contaminated water?

Was there any black slimy stuff (algae)?

Only after we know what you found can we offer sage advice. Sure don't want to address contaminated fuel if all you have is a false alarm from your "water in fuel" sensor!

Brett

[Guest BillAdams]

It's more likely than not that you did not have any water in your fuel. Do you have a fuel filter/separator with a clear/yellow bowl that allows you to see if there is any water? If so, you would be able to look at this bowl and see if there was any water. Water is heavier than diesel and you would see a very distinct line where the water is filling the bottom of the bowl and diesel is on top.

Additives are generally worthless unless you are going to add something to the tank while the coach is going to be in storage for a 6-month winter hibernation to prevent the grown of algae and even then a complete full tank will likely prevent that anyway.

[garykd]

If JimK is replacing the fuel/water separator with factory equivalent, there is no glass to see into.

JimK,

Brett's post made a light bulb turn on. The connector, for the sensor on the fuel/water separator can get water in it. Consider unplugging the connector and drying (hair dryer?) it our really well. After reconnecting the plug ends, consider water proofing the connector. This has not happened to me, but other owners of the same coach/engine we have have reported this.

[mikev]

Hi, ensure the connector is actually on the filter. Last year I had the water in fuel light come on whenever it rained and we were travelling. I got under our coach and found whomever had changed the filters last time had put on two filters of the same part number and neither had a sensor on them . They just tucked up the connector over some other wires. Every time it rained the connector would short out and I would get a light... I replaced the filters withe proper type and connected the wiring-fixed the problem. The previous owner had them changed at a truck facility in Florida.

Live and learn

[jkoeni01]

Brett and All,

Thank you for providing ideas on what may be the cause of the problem.

The fuel was golden throughout. Every time I have drained the filter/separator I've never seen any clear liquid. Also, there is nothing else floating in the fuel.

The sensor was faulty. New one installed and driven since. No false readings of water in the fuel.

JimK

Let's back up a minute.

Tell us what you got when you opened the primary filter/ water separator. Draining into a glass jar is best, as you can see what you have.

Was it all golden yellow (clear clean diesel)?

Was there a separate layer BELOW the golden yellow diesel-- could be clear if pure water or any color of muddy water if contaminated water?

Was there any black slimy stuff (algae)?

Only after we know what you found can we offer sage advice. Sure don't want to address contaminated fuel if all you have is a false alarm from your "water in fuel" sensor!

Brett

[jkoeni01]

If JimK is replacing the fuel/water separator with factory equivalent, there is no glass to see into.

JimK,

Brett's post made a light bulb turn on. The connector, for the sensor on the fuel/water separator can get water in it. Consider unplugging the connector and drying (hair dryer?) it our really well. After reconnecting the plug ends, consider water proofing the connector. This has not happened to me, but other owners of the same coach/engine we have have reported this.

Gary,

What do you use to waterproof the connector?

JimK

[wolfe10]

Silicone di-electric grease is available at most auto parts houses and works well to keep water out of electrical connections.

Brett

[garykd]

Hi JimK,

Thanks for the update. I'm glad you got the problem closed. Brett's post provides the solution for water proofing the connector.