wsj on ulsd/?
 

ME & MY CAR
By JONATHAN WELSH

Is the New Low-Sulfur Diesel
Bad for Older Engines
December 12, 2006; Page D12
Q: I have heard that the soon to be EPA-mandated ultra-low sulfur diesel is bad for my 2006 Jetta TDI. Is this true? What about older TDI's such as a 2003 and a 2001? I would appreciate your advice.
-- Hart Renger,
Fort Collins, Colo.

A: It's a myth. I have heard similar theories, mostly pointing to the relationship between higher sulfur content and favorable lubricating properties that are vital to engine longevity. However, the new lower-sulfur fuels maintain lubricity similar to earlier formulations and can be used safely in older diesel models -- not just Volkswagens. Indeed, according to Mercedes-Benz and a newsletter for a Volkswagen TDI owners club, the older engines will log slightly better fuel economy using the new fuel.

• Have a question about cars? Write to mecar@wsj.com.

We have a 2005.5 or early 2006 Jetta TDI, and of course my MB. Both have logged 2-3 mpg less on ULSD.

I have heard that some have logged better mpg, but I am not one of them. The cars are running fine, though.

WWJD for ULSD?

J would turn RUG into ULSD

nah, he'd turn WATER into LSD... fuel.
John

ULSD has about 1% less energy than LSD, but most people won't notice. Diesel is refined to an ASTM standard, which specifies lubricity, and refiners use additives to meet the standard.

ULSD can cause some seals to shrink, generally before 1993. It also acts as a stronger solvent and may dislodge deposits from the fuel system and cause filter clogging initially.

New 2007 engines designed for ULSD can use a new API-spec oil that allows for longer change intervals.

I work in the pleasure boat industry and this has been a concern as well, especially for those with $100,000 engines. It appears to be mostly a non-issue.

There is a potential for leaks to develope in fuel systems not specifically designed for ULSD. Chevron acknowledges this in a paper FTB-2-1, August, 2005. They also refer to a study by a California Governor's Task Force found at ftp://ftp.arb.ca.gov/carbis/reports/1639.pdf.

Chevron also recommends a maintanence schedule for nitrile rubber seals and the manufacturer's experience with lower aromatics diesel.

Jim W.