Michael Mathe
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AMSOIL Diesel Oils Have Adapted to Overcome New Challenges

I read an article on diesel engines and exhaust emissions in a recent issue of Diesel Power magazine that really hit home. Many diesel enthusiasts are on a quest for more horsepower and torque through a laundry list of modifications that takes the word "stock" and tosses it right out the window. These modifications involve removing many of the systems engine manufacturers have implemented to comply with Environmental Protection Agency (EPA) regulations governing exhaust emissions.

If you've ever read a diesel magazine or talked to anyone in the industry, 2007 was the year that light-duty turbo diesels took a turn for the worse in customers' eyes. It was the introduction of the diesel particulate filter (DPF), which is designed to manage the particulates and soot released by the vehicle's exhaust. David Kennedy from Diesel Power wrote in that article, "How many times have you gotten up in the morning, gone outside, taken a deep breath and said, ‘you know, the air here is just too clean'?" Although you may believe this DPF thing is the worst invention ever, it's in your exhaust system for a reason. So instead of despising it and being confused about what it does and how it does it, let's discuss this device to improve your understanding.

The diesel combustion process is imperfect. For example, diesel fuel does not burn completely, leaving soot as a byproduct. The DPF is a honeycomb-like filter positioned downstream from the exhaust manifold that catches soot. As soot accumulates over time through normal driving, the DPF begins to plug. A diesel engine requires huge amounts of air for combustion and needs to exhale that air through the exhaust very quickly. A DPF that can't pass enough air creates restriction, which leads to reduced power and fuel economy, and eventually could choke off the engine entirely. Original equipment manufacturers (OEMs) designed a process to clean the filter called regeneration. Your truck monitors DPF restriction and automatically begins a regeneration cycle when the pressure exceeds a specific limit. You'll notice when the system activates because a DPF regeneration light will illuminate on the instrument cluster.

So, what is the regeneration cycle? When the DPF is near capacity, soot trapped in the filter is burned, freeing the plugged media and enabling the filter to remain serviceable. Most emissions-compliant turbo-diesel pickups clear the DPF by spraying raw diesel fuel into the cylinder on the exhaust stroke after combustion occurs. Diesel fuel injected on the exhaust stroke does not combust; instead, it travels down the exhaust stream until it reaches the DPF, where it combines with soot and burns. This generates the high temperatures necessary to burn soot trapped in the DPF.

This process is designed to regenerate the DPF and works fairly well; however, since fuel injected on the exhaust stroke does not combust, it tends to wash directly past the piston rings and into the crankcase, diluting the engine oil. That's a pretty big issue considering diesel fuel and engine oil readily mix, resulting in reduced oil viscosity. I've seen oil analyses from trucks with fuel dilution of up to 10 percent. That might seem relatively low, but 10 percent fuel dilution can cause your 15W-40 engine oil to thin to the equivalent of an SAE 20. That's a big reduction in engine protection for engines designed to operate with a 15W-40.

Because this issue reduces the lubricant's ability to protect the engine and extend drain intervals in turbo-diesel pickups, AMSOIL formulated OE 15W-40 Synthetic Diesel Oil (OED) as a cost-effective alternative to more expensive long-drain-interval products. We cannot control the thinning effects the DPF regeneration system has on the oil, so we formulated an oil to accommodate these effects. OE Diesel Oil is highly shear-stable to provide maximum protection against shear-induced viscosity loss, helping to minimize the loss associated with fuel dilution. It provides security in protecting the engine at the OEM drain interval, especially in applications where fuel dilution is an issue. Published, AMSOIL Magazine 08/12. LLC is a large nationwide Dealer of AMSOIL Synthetic Lubricants and is now expanding into your area and surrounding states. If you have a business or are an individual with several vehicles, AMSOIL has several options available that may allow you to Purchase AMSOIL Products at Wholesale Prices. We can show you how to save money and extend equipment life with AMSOIL Synthetic Motor Oils, Lubricants, Filters and Fuel Additives. Please visit the AMSOIL Online Store for more information and to purchase AMSOIL Products.

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