Isuzu has a reputation for producing reliable engines, and they have several engines that are known for their durability and performance. One engine that is often regarded as highly reliable is the Isuzu 4HK1-TC. This is a 5.2-liter four-cylinder diesel engine commonly found in Isuzu commercial trucks and some SUVs. It is known for its robust construction, efficient fuel consumption, and longevity.

Another notable Isuzu engine is the Isuzu 4JJ1-TC. This is a 3.0-liter four-cylinder turbocharged diesel engine commonly found in Isuzu D-Max pickup trucks and some SUV models. It is highly regarded for its power, torque, and reliability.

It's worth noting that the reliability of an engine also depends on factors such as regular maintenance, driving conditions, and proper usage. It's always a good idea to consult with a knowledgeable mechanic or do thorough research on specific models and their engine reliability before making a purchasing decision.