Meeting the challenge

| January 23, 2007

As for leaks, they are only likely to occur with older vehicles – especially older, high-mileage engines that were built before the last reduction in fuel sulfur in 1993. It’s the same kind of situation here as inside the tanks – since the fuel’s different, it affects the seals differently and may cause them to shrink a tiny bit.

“A small number of vehicles may require preventive maintenance in the form of upgrading certain engine and fuel system seals that may not perform well in the transition to the new fuel and could leak,” says Leonardi-Cattolica. Fortunately, she reports, the last change in fuel sulfur content changed the fuel a lot more than this one, so there may not be that many older trucks with problems. Still, you might want to check with your dealer to see whether or not they recommend upgrading to help prevent a problem.

Removing the sulfur also removes parts of the fuel called aromatics that do a great job of lubricating your injection system, a characteristic called lubricity.

Lubricity is very important because only the upper parts of a unit injector or lower parts of an inline pump are lubricated by the engine oil. The fuel-handling internal parts, mainly a tiny plunger sliding up and down in a bore with a very tight fit, are lubricated by fuel alone. Injectors from 2002-2006 run at 26,000-30,000 psi, and 2007 injectors pump at 35,000 psi. Lubrication of a part that works that hard is real important for durability.

But all diesel fuel must pass the very same ASTM (American Society of Testing and Materials) standard for lubricity whether it is LSD or ULSD, and each batch is blended and tested individually by a petroleum distributor before it gets to you. Reports from both engine manufacturers and the American Petroleum Institute are positive when it comes to lubricity. There is no significant evidence of injectors failing because of lack of lube, so far.

While the API represents refiners, the organization also communicates with truckers in order to detect trouble and alert the oil companies of a problem in the field so it can be fixed before trouble gets out of hand. When they say there is no problem with lubricity, it’s likely they are correct.

If you have any fear about using ULSD in your vehicle, ask your dealer whether or not they have heard of trouble to make sure it will work without allowing your injectors to chew themselves up. If you’re still worried after that, you can always purchase a fuel additive made by a responsible manufacturer to put extra lubricity into your tank or buy premium fuel with extra lubricity. Just make sure that if running a 2007 truck with a DPF, the additive is approved for such use. Some contain too much sulfur for use with a DPF.

Cold weather blending
Cold weather blending could become an issue, so be careful. The EPA requires the refiners to make lots of ULSD No. 2, but there is no rule about how much ULSD No. 1 they have to produce. This means that if you are running a vehicle with a 2007 engine, blending in No. 1 or buying blended fuel that is not labeled ULSD is neither permitted by EPA regulations or a good thing to do for the DPF.

But David McKenna, product manager, marketing, Mack engines, says, “Gelling will be a problem handled by an additive program. You waste fuel blending in No. 1 anyway.”

The ASTM diesel fuel standard, in addition to guaranteeing lubricity, requires the fuel to be “additized” (have anti-gel additives blended in) so that it won’t gell at the prevailing wintertime temperature for the area where it is sold. The problem with relying on the standard alone is that you can get gelled up if the temperature is well below normal or if you travel to a colder area after buying the fuel.

For both these circumstances, you can just use one of the many anti-gel additives made by responsible additive manufacturers. If running a 2007 vehicle, just make sure the additive is approved for use with a 2007 vehicle with a DPF because those not approved may have too much sulfur content.

Will you put the wrong fuel in accidentally? That’s not likely, even though there won’t be any kind of special nozzle or tank fitting on 2007 vehicles.

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