hie guys l have 2 MAN trucks which are keeping repeating the same thing. firstly the damage the turbocharger both the top and bottom and the oil goes to the cooler. We than service the turbos charger and fit them back when we want to start the truck the truck suddenly had a diesel knock, we then change the injectors and the truck was fine. The truck only drove for less than 2000km and the top turbocharger seize we then replace it and it has a diesel knock again. These are 2 trucks are doing the same thing and its now the second time what could the problem or l am doing something wrong.