Just noticed today that Nomad attached the following to his signature line...


If anyone has a definitive answer to the DEmulsifier / Emuslifier fuel additive question, based on recent real-world experience applicable to late model Duramax with the latest GM/RACOR water coalescing fuel filter, that would be helpful.

The answer....


DEmulsifiers are ALWAYS best, they force the water to drop out of the fuel.

Emulsifiers make the water BLEND with the fuel (usually with an alcohol of some sort).

Fuel filters remove water better when the water is as dis-similar to the fuel as possible, Emulsifiers make the filter's job harder as the water is now in a blend with the fuel. A coalescing filter is designed to separate dis-similar particles. Most coalescing filter technology is used to separate oil or other mists from compressed air used in ultra sensitive applications. In those situations you keep the filter as cool as you can so that the oil and air are as dis-similar as possible (the oil particles become more viscous than the air) making the filter more efficient.

In the old days, it didn't matter so much...maybe your injectors developed 3000 psi and they only fired once per power stroke. If they did screw up, they cost maybe a hundred bucks...who cared. We had sulfur in the fuel for lube, and all we really wanted to do was prevent a misfire or freeze up if pure water went through the system.

At 30,000 psi and $600 bucks for an injector.....I don't care how "safe" anyone says a fuel with emulsified water in it is. How good is that chemical bond going to hold up at the injector tip? What lubrication qualities does it have now that almost all the sulfur is gone?

Buy a good DEmulsifier, help the filter do its job and let the water drop out IN the filter where it can be drained safely and easily.

do you guys ever drain your filters? i've done it once or twice, but never seen water come out.

I saw water at the drain once....and not much of it. But that was before the latest coalescing version of the filter.....

I do look for water when I change the filter and will see a teaspoon or two every so often. I will also crack open the drain if I'm under the truck for some other reason and let a bit dribble out.

I also do not use a fuel additive on a regular basis, buy my fuel from high volume places (larger truck stops) and my fuel never sits in my tank long enough to go through a bunch of heat/cool cycles that make condensation, I burn a tank or two a day generally....so I'm not a good candidate for water in fuel issues. I don't think it is a big problem any more as fuel stations have better equipment and practices than they used to.

What lubrication qualities does it have now that almost all the sulfur is gone?


Just to clarify. Sulfur was not the lubricant. The process of removal for the sulfur destroys the lubricity of the fuel