Fuel Fool?

[Jon Wehrenberg]

Adding water to fuel is a bad thing, but we northerners had to deal with it so on occasion we added fuel line anti freeze which was basically alcohol. The water with its antifreeze would work its way through the system and if the concentrations reaching the engine were small it would pass though the engine. The engine would stumble a little if a big slug of water reached it all at once.

The water could enter the fuel tank with fuel when refueling, but a lot of it was the result of humid air being drawn into the tank and the moisture content condensing.

There is not a pilot on this forum that is not sensitive to how serious water in the fuel is.

Ironically, around the mid sixties Olsmobile produced a Cutlass with a turbocharged engine and it had water injection to control the burn and prevent detonation.

Growing bacteria and getting moisture in Jet fuel is dealt with in aviation with an additive such as Prist.

[kmuller]

Ben - Steve D'Antonio our VP and author of the article will be at Trawler Fest in Stuart, FL from Monday through Saturday. He will be delivering three lectures, a 2 day lecture on systems (electrical,generator, engine etc.), a morning lecture on running gear/props/shafts and an afternoon hands-on session about tools and failure analysis.

[bill&jody]

so, jon- where does one acquire Prist? if it works for jp5 it outta work for diesel, i would think. no?
do you put it in your bus tank? i've never considered it a problem with 4-wheelers because they run so frequently (i guess). but bugs is bugs. do you treat your bus diesel?

[kmuller]

Bill & Jon - Prist is used in Jet fuel to prevent icing of suspended water particles. Prist lowers the freezing point of suspended particles to minus 46 degrees as found in the upper atmosphere. It is not a product used for non-suspended water. Also Prist dropped the required testing and subsequent certification as a microbiostat (means kills microbes) in 1994. There is some evidence that is does, but the manufacturer no longer makes this claim. Good for jets....not much use in a coach.

[jonnie]

Do any of you guys have a recommended additive for bacteria etc?

John

[kmuller]

John - Hmmmm.... we are very careful about additives (it's an upcoming article subject), because of the perceived panacea effect. It's better to remove the water (bio environment) from the tank with a drain, stripper tube or polishing system, rather than to treat it, an ounce of prevention... Having said that, if needed, our preference is for a product under the name of BioBor, available at West Marine and many auto parts stores.

On a different note, someone else mentioned replacing their fuel lines with copper. This is not recommended by the engine manufacturers as diesel fuel has a chemical reaction with copper.

Hope this helps,

[Jon Wehrenberg]

I don't want to contradict Karl, but I probably use our coach about average or maybe a little more. Nevertheless it sits for extended periods, sometimes as long as several months. Water and contaminents have not been a problem.

We keep it in a garage so temperature swings are minimal, and except for pumping water into the tank when you refuel, the only other way it enters is through the condensation of humidity due to rising and falling temperatures. Above ground bulk tanks are perfect candidates for this type of water accumulation.

Having said that, we have had the Racor filter / separators on our coaches and I can say that in 17 years and around 250,000 miles of travel I have had about ten tablespoons of water evident in the Racor sump and that was all at once, one time only. I think the key is to keep the tanks full, buy the cheapest fuel because that is where there is the most turnover and therefore the freshest fuel, try to avoid refueling when the truck stop is getting a delivery and avoid truck stops that don't change the filters on the pumps regularly.

We have almost exclusively use Flying J and have not had problems.

[Just Plain Jeff]

We have almost exclusively use Flying J and have not had problems.

And now for the rest of the story.

It has been stated numerous times that a certain member uses the B & P method of topping off fuel tanks, which 'releases' sludge and water/condensation each time he fills up. This method results in less concerns about fuel problems.

[Jon Wehrenberg]

If by Band P you mean burp and puke that situation is still there, but under control.

I never fill on the driver's side which was the worst offender when it comes to puking fuel, and on the passenger side I never approach the nozzle unless I know the tank has a long way to go. I just let it shut off by itself and it typically spurts out a cup of fuel which will keep the side of the coach from rusting.

[kmuller]

Jeff - Jon - you are certainly doing everything right to minimize your risk of water contamination and your results show it! Others may not be so lucky. I recently brought a coach out of Florida and after 700 miles the filter was about full of water and trash.

In addition, the refining method itself (particularly with ultra-low sulfer fuel) can have up to 1% water content by weight at the molecular level. Although water at the molecular level generally isn't the problem, it is emulsified and free water that does the damage to finely machined components like injection pumps,high-pressure common rail systems and injectors. The free water is at the bottom of the tank and can not be "burped out".

Monaco (the largest mfg of Class A's) just published an article to their owners regarding bio-diesel (5% bio) and the increased risk of water and other contaminates.....they said "for older engines, a switch to biodiesel could clean off deposits from inside the fuel system and send them into the filter". They recommend "carrying extra fuel filters". In addition Monaco said "Because water is more prevalent in biodiesel, it is more prone to fall prey to microbial growth...". They noted that in a motorhome a filter failure "doesn't always occur in the best area", unlike a trucker who stays on the interstate. These issues are not just with bio, but diesel in general. Fuel quality and filtration is becoming a more and more important subject for all coach owners to become aware of.

As I mentioned in a previous post, we have a very comprehensive article available.

We are in the process of de-fueling a ten year old tank and looking around inside....it will be interesting what we find!