Japanese four-cylinder engine is so reliable still in production after 25 years

Honda K-Series: Impressions and Use Cases

• Several commenters praise the K-series (and related Honda engines) as “indestructible,” fun, and easy to work on, with strong aftermarket support and high power potential on stock internals.
• Swaps into lightweight cars (classic Minis, Civics, even NSX) are described as thrilling but sometimes borderline unsafe due to torque steer and chassis limitations.
• Some note that modern Civics and CR-Vs with K/L-series engines feel exceptionally well balanced and durable in everyday use.

Is It Really “One Engine for 25 Years”?

• Multiple people argue the headline is misleading: the K-series is a family that has undergone significant redesigns (K20A → K20Z → K20C, etc.).
• Suggestion that calling this “one engine in production 25 years” is inaccurate; it’s an evolving platform with shared architecture, not a static design.
• Others counter that this is normal: most manufacturers extend architectures for decades with incremental evolution rather than clean-sheet redesigns.

Comparisons to Other Long-Lived Engines

• Many examples offered that match or exceed 25 years: Toyota A/5A and 2GR, Subaru EJ, Nissan VQ, GM small-block V8 and 3800, Chrysler LA, Ford Windsor/inline-6/Modular, Jaguar XK, VW air-cooled boxer, Rover/Buick V8, Fiat FIRE, Renault Cléon, Ford Kent, Saab H, Volvo modular, Peugeot XUD, simple Chinese single-cylinder diesels, etc.
• Consensus: long-running engine series are common; K-series is good, but not unique in lifespan.

Reliability vs Emissions and Efficiency

• Commenters stress that new engine designs are driven more by fuel economy, emissions, and regulations than by reliability limits.
• Older engines (e.g., some diesels, Cleon, XUD, 1.9 TDI) are praised for robustness but criticized as environmental or fuel-economy liabilities under modern standards.
• Discussion that even tiny efficiency/emissions gains can justify redesigns at production scale.

Modern Engine Fragility and Design Trade-offs

• Multiple posts note recent engine failures and lawsuits across manufacturers, attributing issues to: thinner oils for marginal MPG gains, extended oil-change intervals, plastic components, and aggressive turbocharging.
• Examples include problematic wet timing belts, oiling-system edge cases, and bearing/timing issues in several modern engines.
• Some see this as analogous to over-driven light bulbs: meeting efficiency rules at the cost of longevity.

Japanese Reliability Stories

• Numerous anecdotes contrast durable Hondas and Toyotas with more failure-prone European cars of similar age/mileage.
• One theme: Japanese designs often feel “overbuilt,” tolerant of abuse and minor neglect—though claims of running “fine” with no oil/coolant are strongly disputed as exaggerations.