In diagnosing ash plugging in a DPF, which factors were proposed as causes by the technicians?

• A. Oil compatibility with DPF
• B. Engine wear causing high oil consumption
• C. Both A and B
• D. Neither A nor B

Answer: (C)

Ash plugging in a DPF happens when ash-forming material, not soot, accumulates in the filter and isn’t burned away during regeneration. Two factors technicians flagged can contribute to that ash load: the oil’s compatibility with the DPF and the amount of oil entering the combustion chamber due to engine wear. Some lubricants leave more ash in the exhaust, especially higher-ash or high SAPS oils, which adds to the DPF ash burden. At the same time, if the engine is worn and consuming more oil, more oil-derived ash ends up in the exhaust, increasing the risk of plugging. Because both factors can increase the ash that remains in the DPF, the best answer is that both were proposed. In practice, addressing ash buildup involves considering oil formulation choices and monitoring oil consumption to prevent excessive oil-related ash.