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HK-HG Monaro / GTS

1968-1971 / Coupe / Australia

All HK-HG Monaro / GTS problems All workshop issues
Common Engine, Holden Six (186ci) and V8 (253ci)

Valve Train Wear (253 V8)

Symptoms

Ticking or clattering from the top of the engine. Reduced power.

Cause

The Holden 253 V8 uses adjustable rocker arms on a shared shaft. The rocker tips and shaft wear with age, particularly if the rockers haven't been adjusted regularly.

Fix

Inspect and replace worn rockers and shaft. A Yella Terra roller rocker conversion ($400-800) eliminates the wear issue permanently and adds a useful amount of top-end power.

Cost mentioned in fix
$400-800

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Other known issues

Common Engine, Holden Six (186ci) and V8 (253ci)

Oil Leaks, Rear Main Seal

Oil drips from the bellhousing area. Oil accumulates on the underside of the engine and transmission.
Critical Engine, Chevrolet V8 (327ci / 350ci)

Intake Manifold Gasket Leaks

Coolant leak at the front or rear of the intake manifold. Coolant may drip externally or, worse, leak internally into the engine oil. May also cause a vacuum leak, resulting in rough idle and poor fuel economy.
Common Engine, Chevrolet V8 (327ci / 350ci)

Rochester Quadrajet Carburettor Issues

Hesitation on acceleration (bog), flooding, fuel smell, hard starting when hot, black smoke, erratic idle.
Critical Engine, Chevrolet V8 (327ci / 350ci)

Overheating Under Load

Temperature gauge climbs on highway drives, particularly towing or climbing hills. May push coolant out the overflow. Engine pings (detonation) under load.
Common Engine, Chevrolet V8 (327ci / 350ci)

Hydraulic Lifter Noise

Ticking or clattering from the top of the engine that varies with RPM. May be audible at idle and disappear at higher RPM, or vice versa.
Common Transmission

Muncie 4-Speed Synchro Wear

Grinding on gear changes, particularly second and third gear. Difficulty selecting gears under load.
View all 18 HK-HG Monaro / GTS problems