Do you need low ash motor oil? You will need it if you buy an '07 emissions-compliant diesel truck, but the benefits of running a low ash formula will make you want it in your rig now. "Low ash" refers to the amount of solid material that is left behind when the oil burns. By reducing the ash content, oil manufacturers will help cut down the amount of deposits left in your engine, which will diminish wear and reduce emissions.
Speaking of emissions, the development of low ash oil comes from the lubrication needs of the new cleaner versions of the Power Stroke, Cummins, and Duramax engines that will hit the streets in 2007. Shell Lubricants estimates it will take 60 of these new trucks idling to equal the emissions of one idling truck from 1988-and that's 10 times better than the trucks being sold today.
The '07 Dodge Ram 3500 Chassis Cab will be the first American truck sold that meets the new emissions requirements. It features a larger 6.7L displacement to help keep cylinder and exhaust temperatures low. It's also equipped with a large Exhaust Gas Recirculation system and a Diesel Particulate Filter that will become clogged unless CJ-4-compliant low ash motor oil is used. General Motors and Ford will soon be building new turbodiesel engines that will have similar emissions equipment.
Ultra Low Sulfur Diesel (ULSD)
One of the main reasons for this massive reduction in emissions is our nation's upcoming conversion to Ultra Low Sulfur Diesel fuel. This new standard reduces the sulfur content in diesel from the current ratio of 500 parts per million down to just 15 ppm at the pump. It's predicted that refiners will actually produce fuel with only an 8 ppm sulfur content to allow for contamination during the distribution process (oil companies face a $1 million fine for exceeding the 15 ppm limit). In addition to the cleaner fuel, turbodiesel trucks will need to run complicated emissions-scrubbing components that will be most effective when the oil meets specific standards set by the American Petroleum Institute.
To meet American Petroleum Institute's CJ-4 standard, oil must be processed so it's more resistant to heat and leaves low amounts of ash deposits when it does burn off. By producing fewer deposits, it will be less likely to congest the Diesel Particulate Filters that will be standard equipment on diesel trucks the OEMs will start selling in 2007.
API CJ-4
The American Petroleum Institute's CJ-4 standard for motor oil is specifically designed for the new '07 emissions-compliant diesel powerplants that will be running on ULSD. Since this fuel does not benefit from the lubrication of sulfur, the motor oil has to work extra hard. It can be used in all diesel trucks made after 1993 but may cause leaks in older motors because they lack synthetic seals and hydraulic lines. To be certified as compliant, blends must be able to handle high temperatures and deal with additional soot being processed through the engine, thanks to the exhaust gas recirculation systems.
Exhaust Gas Recirculation (EGR)
The EGR systems on the new '07 turbodiesel engines are much more than a valve that routes spent gasses into the intake. The new, heavy-duty EGRs are up to twice as big (and heavy) as the units being used today. They include a large heat exchanger that helps cool the gasses before they are routed back into the intake system. By adding the cooled exhaust to the cylinders, oxygen is removed from the combustion, which reduces nitrogen oxide emissions and reduces heat in the cylinders and exhaust system.
The new low ash oils will reduce sludge deposits in all diesel engines. The oil pan in the top half of the photo is from an engine filled with the new Shell Rotella T with Triple Protection designed to meet API CJ-4 specifications. The other pan was from an engine using the previous standard: Shell Rotella T CI-4 Plus. Even if you don't buy a '07 emissions-compliant diesel truck (and own a diesel made after 1993), you should consider running this new oil.