Blowin' Smoke

An Editorial by dieselmann
Volume 17; October 06: Ultra Low Diesel Fuel Concerns

Begining in 2007, the EPA has mandated a drop in sulfur content in diesel fuels from 500 PPM found in low sulfur diesel to 15 PPM. This new Ultra Low Sulfer Diesel (ULSD) is designed to reduce hydrocarbon, oxide of nitrogen and particulate (soot) emissions. Currently 80% of diesel fuel produced for highway use in the US needs to be ULSD, but by 2010 only ULSD will be available. California required all highway use diesel to be ULSD by July 15, 2006.

At this time what the effects to fuel systems and economy is unknown. In the past when sulfur was reduced from 1500 PPM to 500 PPM, the process used to remove the sulfur also reduced lubricity. Along with the reduction of sulfur, aromatics were reduced, and this resulted in fuel seals and hoses leaking. We saw a lot of failed injection pumps and failed o-rings and hoses when the low sulfur diesel was introduced in California back in 1992. As low sulfur diesel became more widely distributed, these problems showed up in other areas of the country as well.

According to the Clean Diesel Fuel Alliance web page, you should monitor your truck's fuel system for leaks and the fuel filter for plugging as ULSD is introduced. Additional lubricity and corrosion inhibitors are needed with ULSD, and there may be a reduction in performance and economy as there may be a reduction in energy content of the fuel. By rights, the fuel distributors will be adding conditioners to prevent the problems we saw in the older trucks.

The 7.3 and 6.0 PowerStroke engines were designed to run on low sulfur diesel fuel. The EPA mandates that all 2007 diesel engines use ULSD, but the 6.0 PowerStroke in the 2007 trucks is considered a hold-over 2006 design. I would advise using a fuel conditioner that increases lubricity and cetane, and replacing the fuel filter more often in these older models until the effects of ULSD becomes known. The new 2008 6.4 PowerStroke is designed to run on only ULSD.

The EPA has mandated that fuel pumps be labeled show what fuels are being dispensed, except in California where all fuel is supposed to be ULSD. The pump should be designated Ultra Low Sulfur Diesel, 15 PPM Sulfur Maximum; required for 2007 and later engines, Low Sulfur Diesel, 500 PPM Sulfer Maximum; prohibited from use in 2007 and later engines, or Non-Highway Diesel Fuel, May Exceed 500 PPM Sulfur; prohibited from use in highway vehicles.
If you see no label, assume it is ULSD.

Clean Diesel Fuel Alliance
Pump Labels (PDF)

Charles David Ledger; dieselmann2003

Questions or comments:
dieselmann@intellidog.com

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