If you have a California car and it stills has the "Trap Oxidizer" in place it could be the source of the problem. The catalyst has a tendency to break down, send material directly into the exhaust impeller, and the combination causes a hole to develop in the exhaust housing. I believe MB issued a bulletin regarding Turbo-Diesels for model year 87, would be worth exploring if your vehicle is equipped with a “Trap Oxidizer!”

Good Luck