When doing the head on my L series there are parts on these that are the same or close enough to be the same as a TD5, but dont cause problems like on the TD5

Found that the plastic head dowel are the same part number as a TD5, But L series dont suffer from the head moving and blowing like a TD5. The dowels were in perfect shape and not starting to shear at all. Usual head gasket issues with L series are due to poor coolant maintenance and the head gasket rusts. I did fit steel dowels from a TD5 Though

Water pumps although not the same part number look identical. this is the 1st water pump I have changed on a L series and it wasnt leaking. I changed it due to having 200000km on it. and they dont last for ever.
Im not having a dig at a TD5 I think they are a great engine, just cant figure out why these issues arent seen on a L series with the same or similar parts.