Your DPF is Clogged with Engine Oil


If you own a truck with a diesel engine that’s traveled a couple of hundred thousand miles, you might notice a loss in fuel efficiency or an illuminated warning light on the truck’s dash. A likely problem could be that your truck’s diesel particulate filter (DPF) is clogged. An engine that runs with a clogged DPF results in backpressure that causes your engine to work harder and decreases your fleet’s fuel efficiency due to the need to burn more fuel. Your best solution is to completely replace or to remove and thoroughly clean your truck’s DPF.

A thorough cleaning requires significant downtime—TravelCenters of America notes that its cleaning process can take more than 10 hours, and that isn’t even taking cost into consideration. Completely replacing a DPF can cost anywhere from $3,000 to $10,000, according to the Universal Technical Institute. Needless to say, the process is a hassle. To prolong the need to clean or replace a DPF, Chevron Products Company, a division of Chevron USA, developed an engine oil to combat DPF clogging.

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In November of last year, Chevron announced a new heavy-duty engine oil, Delo 600 ADF with OMNIMAX (a patented technology that delivers maximum protection to the engine and emissions system). This engine oil reduces the rate of DPF clogging to extend service life, resulting in money saved and less downtime.


To understand how Chevron’s Delo 600 ADF reduces the rate of DPF clogging, let’s first discuss how a DPF is clogged.

Several years ago, diesel particulate filters were implemented to decrease harmful particulate matter from diesel exhausts. These filters collect up to 98% of emissions in the form of ash and soot. A diesel engine’s regeneration cycle burns away most of the soot from the filter. However, the ash—material from metallic lubricant additives—does not burn away during a regen cycle. Repetitive use of diesel equipment leaves a DPF clogged with ash, requiring fleet owners to remove and clean or replace the DPF.

Before developing the new oil, Chevron discovered through testing and studies that 10% of the ash that clogs the DPF comes from engine wear and contaminants in the oil or improperly filtered air. The other 90% comes from engine oil, not diesel fuel, as many would believe. It’s been 10 years in the making, but Chevron’s new engine oil formulated to slow DPF clogging is finally ready for the market.


Chevron’s new Delo 600 ADF is somewhat revolutionary. Yes, it meets the specifications of API CK4. Yes, the synthetic blend is available in SAE 15W-40 and 10W-30. But it’s also formulated with an additive system that features 60% less sulfated ash than current heavy-duty engine oils. Because Delo 600 ADF uses additives that create 60% less sulfated ash, trucks and equipment could see an extended DPF service life of more than twice the amount they are currently running.

To prevent a buildup of ash, Chevron removed a common engine oil ingredient from 600 ADF—Zinc Dithiophosphate. The primary role of Zinc Dithiophosphate, commonly known as zinc, is to form a protective film that prevents metal-to-metal contact within the engine. But an absence of zinc in 600 ADF doesn’t mean there is no anti-wear protection. Engines that have undergone field and lab testing using 600 ADF show very little to no wear.

Chevron Products Company’s manager of industrial and coolants brands, Dan Holdmeyer, says one engine used in field trials, a Cummins ISX with drain intervals at 60,000 miles, was torn down at 500,000 miles. Its components looked good enough to put back into the engine and head back into the field. Dan says Chevron is still testing engines to see if these trucks can reach 1 million or 1.5 million miles with 600 ADF. Chevron’s target with this new oil is to double the DPF service life of diesel engines set by OEMs.

Dan says Chevron is also expecting longer drain intervals with the new engine oil. An oxidation test with Delo 600 ADF went twice the required duration for API CK4 oil.


Dan says he’s heard a lot of talk in the industry that the DPF is like a “black box” to some diesel engine truck/equipment owners. They’re unsure how to correctly maintain the filter to optimize service life on both the filter and the engine. Chevron’s new oil should take the guesswork and worry out of the equation for fleet owners and managers for three reasons. Those reasons are found in the oil’s name.

The brand named the new oil after the oil’s greatest attributes. ADF stands for aftertreatment protection, drain interval extension, and fuel economy retention. The purpose of engine oil is aftertreatment protection, and we’ve already touched on the drain interval extension. The fuel retention comes from less backpressure from a clogged DPF as well as using less fuel in the active or manual regen process as there is less ash on the filter. Dan says Delo 600 ADF should give fleets a 3% fuel retention compared to other oils. This is because the new oil saves diesel engines from burning through extra fuel due to backpressure.

The new oil was showcased last month at CONEXPO in Las Vegas. Dan says the response was very positive with several customers placing orders for Delo 600 ADF with their Chevron distributors right in the booth!

Delo 600 ADF is currently available in the US and Canadian markets with a planned rollout in Latin America and Europe around September or October of this year.


Find out more about the new engine oil, Delo 600 ADF, visit

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