Cleaning out the carbon is a MUST anytime you change glow plugs in these engines. If you don't do this your engine will not run as well a startup and it will shorten the life of the new plugs. This is a high quality custom made glow reamer. All steel body. Made by Kent Bergsma. Much stronger that the common aluminum type available. Sorry, NO instructions included.
WARNING: Always use anti-seize compound when replacing the long glow plugs in these later engines.
Preventing Mercedes Benz Diesel Premature Glow Plug Failure by Kent Bergsma