Mitsubishi 4G52, 4G54, 4G55 engine 2.0L, 2.6L Workshop Manual (P/N 30521)

This 71-page PDF set combines the 67-page Mitsubishi Engine 4G5 Series Workshop Manual with the four-page Chrysler Australia brochure Chrysler’s Exclusive Astron Silent Shaft Engine. The workshop publication is engine section 11A, issued in October 1990 as Publication No. PWEE9055. Its layout follows engine assemblies and factory service points rather than vehicle chassis systems.

• Covers cylinder-head removal and installation, valve and guide inspection, valve-seat reconditioning and replacement, stem-seal service, and jet-valve disassembly and reassembly.
• Separates timing-chain repair for engines with and without the Silent Shaft system, including sprocket timing-mark alignment, chain-guide service, balance-shaft chain adjustment, and oil-pump drive-chain adjustment.
• Details rocker-arm, rocker-shaft, and camshaft repair; lash-adjuster air bleeding and leak-down testing; and jet-valve or conventional valve-clearance adjustment.
• Documents lubrication repair for involute-gear and trochoid oil pumps, with relief-plunger inspection, Silent Shaft rear-bearing service, thrust-plate installation, and oil-flow diagrams.
• Handles piston-pin press work, piston-ring and connecting-rod inspection, crankshaft bearing-clearance checks, rear oil-seal replacement, flywheel and drive-plate service, and cylinder-block boring and honing.
• Includes component-specific torque tables, sealant specifications, service limits, oversize and undersize data, inspection values, and a factory special-tool list with Mitsubishi tool numbers.
• Adds an illustrated explanation of the Silent Shaft operating principle and identifies the Astron 2000 as 4G52 in the Chrysler brochure.

Coverage and Variant Identification

The factory workshop manual carries the broad 4G5 Series title, but its general specification table is for a 2,555 cc engine configuration. It does not break the repair procedures into individual 4G52, 4G54, 4G55, or 4G56 chapters. The explicit 4G52 identification appears only in the supplemental Chrysler brochure, which is background material rather than a repair section. The PDFs also contain no model-by-model vehicle application list or serial-number range. Fitment should therefore be checked against displacement and the engine’s actual hardware rather than assumed from a listing title or vehicle badge.

Variant handling is one of the manual’s stronger points. Procedures are split for engines with or without Silent Shafts, with or without jet valves, and with or without lash adjusters. Destination-specific differences are called out for Europe/Australia and General Export versions, while the intake-manifold section identifies the coolant-temperature sensor used with an electronic-control carburetor. The crankshaft inspection material separately flags the special-surface crankshaft used on turbocharged engines.

Factory Procedures, Tools, and Illustrations

The cylinder-head repair material goes well beyond gasket replacement. It covers head and manifold-surface inspection, valve and spring checks, valve-guide replacement, valve-seat reconditioning or replacement, jet-valve service, stem-seal installation, and the required tightening sequence. Valve-train work includes camshaft inspection, rocker-shaft orientation, bearing-cap identification, lash-adjuster bleeding and leak-down testing, and final clearance adjustment where applicable.

Representative factory tools include MD998250 and MD998251 for the Silent Shaft rear bearing; MD998308, MD998309, and MD998310 for jet-valve work; MD998440, MD998441, and MD998442 for lash-adjuster testing and air bleeding; MD998183/MD998184 for piston-pin service; and MD998376 for the crankshaft rear oil seal.

Useful drawings include engine sectional views for Silent Shaft and non-Silent Shaft configurations, matching lubrication-system diagrams, plated-link timing-chain alignment views, rocker-shaft mating-mark and bearing-cap identification drawings, piston-ring gap-position diagrams, and crankshaft-bearing/rear-seal section views. The Chrysler brochure adds a Silent Shaft operational-principle diagram and labeled Astron engine cutaways.

Repair Cautions and Scope

On Silent Shaft engines, incorrect oil-pump gear timing changes balance-shaft phase and produces vibration; rotating the thrust plate to chase its bolt holes can twist or damage the O-ring. The manual also warns that piston oil-ring side rails can break if installed with a conventional ring expander, and that the special-surface turbo crankshaft must not be machined undersize.

This is an engine-only repair manual section, not a complete vehicle manual. It contains water-pump, thermostat, water-outlet, hose, and coolant-sensor service, but no full cooling-system diagnosis chapter. It does not include carburetor or fuel-system overhaul, chassis wiring, transmission, suspension, brake, or body repair information. Because the procedures involve press-fitted parts, heated shrink-fit components, rotating timing assemblies, and staged fastener tightening, use the relevant factory safety controls and vehicle-level isolation procedures before beginning the work.