W126

Always replace these banjo bolt washers when removing the oil filter housing. All 5-cylinder turbo engines.

Your diesel should run between 80-85C. It if runs over 95C, it is not healthy for the engine. This might cool it down 5C unless you have major problems like cylinder head crack or leaking head gasket.

10mm - 13mm - 14mm - 17mm are the most common fastener sizes and these are unique for special uses.