Ball Family Bus

As of Sept 2006, all on-highway diesel sold in the US is now ULSD. And all diesel vehicles manufactured for model year 2007 and beyond are made to use it exclusively. Lately I’ve been reading about some problems it can cause with older engines lately.

While sulfur isn’t actually a lubricant itself, it combines with the nickel content of the alloys in the engine to form a new alloy that is lubricating. By drastically lowering the sulfur content of the fuel, this lubricating factor is missing and will cause extra wear on the engine. Apparently, the distributors of the fuel are supposed to add lubricating agents, but it’s not controlled or uniformly done.

There are a lot of additives that can bring back the lubricity that is missing. I read a test report covering various popular additives (see links below) and one of the most effective, most widely available, and cheapest additives is plain old (ashless) two-cycle oil. The concentration that I’ve seen recommended is 1oz per gallon of fuel.

So I went to Wal-Mart and bought a gallon to try in the bus and possibly in the Jetta TDI. There are people who keep very detailed logs and report that a nice side effect of using it is improved fuel mileage. So hopefully it’s enough to offset the cost of the oil - making it a break even proposition. Either way, it looks like a fairly easy way to improve the life of the engine.

By the way, ULSD not only reduces lubricity but also reduces the amount of energy available in the fuel by about 1% and it’s estimated that the extra refining adds $0.05 - $0.25 per gallon to the cost of the diesel. Gotta love the EPA….

References:

• Wikipedia entry for ULSD
• Lubricity Additive Study Results
• Article about adding 2-cycle oil to diesel