Caterpillar 3408E

The Caterpillar 3408E is a turbocharged, aftercooled V8 diesel from Cat's 3408 industrial engine family, displacing about 18.0 L (1,099 cu in) with a 137 mm x 152 mm (5.4 in x 6.0 in) bore and stroke and a 14.5:1 compression ratio. It's the fully electronic member of the family, running Hydraulic Electronic Unit Injection (HEUI) fuel delivery under an ADEM-series ECM in place of the mechanical injection pumps on the 3408, 3408B, and 3408C. Net dry weight isn't published specifically for the 3408E; across closely related 3408-platform variants it clusters roughly 1,640-1,820 kg (3,600-4,000 lb), depending on turbocharger, aftercooler, and accessory dress. Cat built the 3408E generation roughly from the mid-1990s into the early 2000s, following the mechanically governed 3408, 3408B, 3408C, 3408DITA, and 3408TA, and paired it in factory documentation with the V12 3412E. Net power runs roughly 336-429 kW (450-575 hp) across most industrial and off-highway ratings, varying by rating class and configuration. Cat offered it as a bare industrial power unit, a generator-set engine, a marine engine, and a truck/machine engine used in off-highway and underground haul trucks and wheel-type equipment of that era. It shares a base block with the unrelated G3408/G3408C natural-gas industrial engine, a separate spark-ignited family.

The 3408 family's defining change across generations was the move from mechanical to electronic fuel control. The 3408 and 3408B ran mechanical injection pumps and governors; the 3408C refined that architecture; the 3408E replaced the pump train with HEUI injectors and ECM-controlled timing, tightening emissions, fuel economy, and diagnostics while keeping the same basic V8 block. Cat also built the 3408E with two injector designs across its production run, and the two aren't interchangeable within one engine because ECM calibration differs between them - a detail that matters when sourcing injectors today. Block-level mechanical parts often carry over across 3408 generations, but the 3408E's hydraulic pump, injectors, and ECM are specific to the electronic generation and won't fit the mechanical engines. Caterpillar never built a direct one-for-one V8 replacement; the C-series lineup - C15, C18, C27, and C32 - inherited the same general power band with full electronic control for new, emissions-compliant builds. With the 3408E out of production, used units remain common in industrial standby, marine, and oilfield service. The parts market leans on rebuilt HEUI pumps, injectors, and turbochargers alongside mechanical wear parts shared across the wider 3408 platform, and matching injector type to ECM calibration is the detail that trips up the most rebuilds.

Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.