Originally Posted by q240z
Well, somebody needs to go tell that to the good people at boatdiesel.com, because there are plenty of threads over there about ULSD not providing the lubricity the older engines require. Kinda like back in the day when they switched from leaded gas to unleaded and there were concerns about the old engines burning up their valve guides. Then again, I don't know if that turned out to be just an old wives's tale or not...
**** the internet. There's too much information! lol
I have seen people on the internet ranting and raving about it for awhile, and can say with absolute certainty that it is a steaming load of BS.
The new fuel only represents a chemical difference of Sulfur<500ppm to Sulfur<15ppm. The original concentration of less than 500ppm was already so small that it is logically impossible that it could have had any significant lubricating properties at all at those levels, and even more impossible that the S<500ppm to S<15ppm change could have some mysterious engine-killing effect.
Are you aware of how small an amount you are talking about with ppm calculations? A part-per-million is equal to less than one single drop of water out of a pool of 50 litres. So think of having something like twenty-five 2-litre bottles of Coke lined up, and then open just one of them and take out just a single drop of liquid, and that's a good illustration of the scale of the quantities we are dealing with here.
It is a stretch to think that these amounts of ANYTHING, let alone sulfur, could have any lubricating effect on hundreds of pounds of moving iron. Even if that was a concern, diesel has lubricants added to it by the manufacturers anyway.
The problems people are having don't relate at all to the sulfur content. Rather, the new fuel is mandated to contain detergents, very much like gasoline. So, what happens is that switching fuel to the new composition provides a shock to the engine because the new blend with detergents built-in starts knocking all the years of built-up crud loose. Those deposits can then cause issues that need to be addressed, usually with the fuel system and valves.
But that's all that is happening....the fuel itself is not damaging the engines.