I think he is implying that the engine is virtually indestructable, denoting reliability. But since it is a mechanical device, it will eventually fail.

__________________
2005 Accord Hybrid (Wifes)
1995 Subaru Impreza L AWD (Snow car)
1984 GMC Sierra 1500 (Mine)
1983 300CD Best $ I ever spent. (Mine)
1984 190D (sold and glad I did)
1983 300D (sold and wished I hadn't)