Caterpillar 323D L

The Caterpillar 323D L is a mid-size crawler hydraulic excavator in Cat's D-series medium excavator line, with an operating weight that runs roughly 22.3-23.5 tonnes (about 49,200-51,800 lb) depending on undercarriage, boom/stick length and counterweight configuration. Depending on the production series and the emissions market a given unit was built for, it left the factory with either the mechanically governed Cat 3066 ATAAC turbocharged six-cylinder diesel (non-emissions-regulated markets) or the electronically controlled Cat C6.4 ACERT turbocharged six-cylinder diesel (Tier 3/Stage IIIA-regulated markets), both roughly 6.4 L units rated in the 104-110 kW (140-150 hp) range at 1800 rpm. Cat produced the 323D L from roughly 2006/2007 through 2014, slotting it between the smaller 320D/320D L and larger 324D/325D; the "L" designation denotes its long-undercarriage configuration, offered alongside related LN, S and SA variants, and Cat sold it with a choice of boom and stick-length combinations to tune dig depth and reach for trenching, mass excavation and utility work.

The D-series update replaced the prior 323C L generation, bringing a revised cab and hydraulic-system tuning, and, on ACERT-engine units, electronic engine and common-rail fuel-injection control for tighter emissions compliance, while markets outside those rules kept the simpler mechanical 3066 engine for lower cost and easier field service; buyers and parts sourcers still need to confirm which engine family a given serial prefix carries before ordering engine components. The 323D L was itself succeeded by the Cat 323E L (roughly 2012-2016) and later the letterless Next Generation Cat 323 platform. It remains one of the more widely traded machines in the used 20-25 tonne excavator class today: old enough to be affordably priced, built on a long production run sharing components across the 320D/321D/323D family, so filters, hydraulic parts, undercarriage components and seals stay readily available on genuine and aftermarket channels, keeping repair and rebuild economics attractive against buying new.

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.