Who is correct concerning the type of oil needed to prevent damage to exhaust aftertreatment systems?

To effectively prevent damage to exhaust aftertreatment systems, the type of oil used in diesel engines is crucial. Low ash content oils are particularly important because they help minimize the buildup of particulate matter within the diesel particulate filter (DPF) and other components of the exhaust aftertreatment system. High levels of ash can lead to clogging and reduced efficiency of these systems, which are designed to reduce harmful emissions and maintain compliance with environmental regulations.

While low-sulfur oils are also beneficial for reducing exhaust emissions and protecting components, the specific focus on oil with low ash content is more directly related to safeguarding the exhaust aftertreatment systems. This is why Technician B’s assertion about the importance of using oils with low ash content is correct in the context of protecting these systems, making this the best choice in the question.