1984 Mercury Grand Marquis Service and Repair Manual

This factory service and repair manual for the 1984 Mercury Grand Marquis has two engines to keep straight and three bodies to fit them into. The 5.0L V8 measures 302 cubic inches and the 5.8L measures 351, and both are naturally aspirated overhead-valve designs running on gasoline. The two-door sedan, four-door sedan and four-door wagon share most of their mechanical content, while Base, Colony Park and LS differ in equipment — which matters most in the wiring diagrams, where the circuits drawn depend on how the car was ordered.

Engines covered

• 5.0L V8 (302 cu in) — OHV, naturally aspirated, gasoline
• 5.8L V8 (351 cu in) — OHV, naturally aspirated, gasoline

Body styles covered

• 2-door sedan
• 4-door sedan
• 4-door wagon

Trims covered

• Base
• Colony Park
• LS

Known issues on the 1984 Grand Marquis. Two recalls appear on the federal record. One is a restraint problem: the bolts holding the shoulder belt D-ring are anchored in material that cannot properly support them, so the anchorage falls short of the federal strength requirement. The other covers replacement fuel pumps that can leak gasoline and create a fire hazard. Owners have logged 23 complaints, led by the electrical system with seven, the engine and cooling system with five and speed control with four. Belt anchorage torque values, fuel delivery checks and the wiring diagrams for those circuits are all in this manual.