When trap oxidizers were failing on MB diesels of '85 - '87, Mercedes recognized this and warranteed the systems for life. After thousands upon thousands of oxidizer replacements in a decade's time, Mercedes came out with the oxidation catalyst for newer diesel models. They decided to fit the catalyst to the older California model diesels and be done with the TO replacements for good. In many cases this involved a brand new exhaust front to back, brand new turbo, and a brand new head. Serious $$$$ on each '85 - '87 California diesel they made. That's the MB that I used to know!