Hylomar 1.3oz tube (40ml) gasket dressing and thread sealant. The worlds most fabulous goop! You've got your standard goop, and then you have Hylomar. This is way better than the stuff you can buy at the local discount store. VW says that gasket sealer is unnecessary. They also say that diesel head gaskets don't leak. We recommend a Hylomar, Hylomar is a polyester polyol-based compound that turns from a gel into flexible putty within minutes of application. Originally developed by Rolls Royce where it performed under the most stringent aerospace tolerances. Hylomar brings superior qualities to automotive applications. Withstands temperatures from -60F to 600F.
Since you are using the worlds best goop (also available in a spray shown on this page), you should consider treating your diesel engine to (the worlds best) high performance fully synthetic oil. It provides superior wear resistance and reduces sludge build-up for improved engine life.