There is an article in the March / April 1997 issue of The Star magazine about the infamous Trap Oxidizer.

Frank King, the long time technical editor of the Star Magazine, wrote a long two page article on this Trap Oxidizer.

He basically says that it was introduced in 1985 on California versions of models with 617.592 and 617.591 diesel engines, and was also done in 1986 to California cars with 603.961 engines. In 1987, use of trap oxidizers was extended to cars with diesel engines 603.960 and 603.961 in all 50 states.

"The component was a filter known as a trap oxidizer, designed to meet California emission standards. Located between the exhaust manifold and the turbocharger, the trap oxidizer is a monolithic labyrinth of ceramic rods housed in a steel cylinder.

Due to the extreme range of temperatures to which the trap oxidizer was subjected and the vibration inherent in the application, the ceramic monolith did not have the expected service life. Sometimes pieces of the ceramic, ranging in size from dust to chunks, broke off and were blown into the turbocharger. The abrasive ceramic particles could damage the turbo blades. As a result, Mercedes-Benz instituted an extended exchange or warranty policy. Owners of affected cars were protected from repair expense due to trap oxidizer failures.

Mercedes Benz developed a new device called an oxidation catalyst with sufficient durability to replace the trap oxidizer.

Owners who have had the job done report a noticeable performance improvement after installation of the oxidation catalyst, probably due to the decrease in exhaust back pressure."

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".