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Replacing School Bus DPF Mercedes Diesel Engine

mercedes dpf diesel engine replacement

Servicing the DPF (diesel particulate filter) is now a regular preventive maintenance step that requires removal and cleaning or replacement off the shelf depending how much you want to spend and how much down time you can put up with. I have some photos of one of our pusher school buses that required a new DPF because it was regenerating on a daily basis…much more than models we are running with the same specifications.

Below the art of removing and installing the DPF requires some gentle guidance. A hoist and a transmission jack helps a lot and allows the tech to line up the filter with the main body which uses gaskets to seal the connection. Once the clamps are tight the sensors and hoses can be reinstalled.

skilled mechanic replacing school bus engine

Looking inside the casing you can see the DOC which is the diesel oxidation catalyst. This is where the diesel that is funneled down the pipe to create heat and the catalyst oxidizes the harmful emission gases. Since this engine is a 2007 this is the second filter to be replaced.

used dpf from school busThe used DPF (below) is contaminated with soot so it will go to one of the local shops for cleaning. There are 2 stages of cleaning depending on how much contamination there is in the DPF. Two stages of cleaning are available.. the latter being a high heat bake job that gets rid of the soot and ash that is clinging to the filter.


top view of used dpf

side view of used dpf

The new filter is ready to be installed. It’s a clean DPF that we bought from the dealer. It’s right off the shelf so there’s no waiting compared to removing the filter and taking it to a shop. The down time would be at least 2 days. Once the new DPF is installed the serial number has to be entered into the vehicle database which can be done with the Detroit Diesel software.