Comparing Lifespan of Used Engine Models When buying a used Japanese truck, the engine is the heart of the decision. A well-maintained engine ensures long-term reliability, while a weak one may cause costly downtime. For buyers in export markets, understanding the typical lifespan of different engine models is essential. Japanese manufacturers such as Isuzu, Hino, Mitsubishi Fuso, and UD Trucks design engines to handle tough workloads, and their performance varies across models.