1989 GMC R2500 Service and Repair Manual

This factory service and repair manual for the 1989 GMC R2500 covers the four-door crew cab pickup with three naturally aspirated overhead-valve V8s: a 7.4L of 454 cubic inches, a 6.2L diesel of 379 cubic inches and a 5.7L of 350 cubic inches. Base, High Sierra and Sierra Classic trims are listed. The gap between a large gasoline V8 and a diesel is wide enough that little carries over between them, so the book documents each with its own procedures, specifications, torque values, wiring diagrams and diagnostics.

Engines covered

• 7.4L V8 (454 cu in) — OHV, naturally aspirated, gasoline
• 6.2L V8 (379 cu in) — OHV, naturally aspirated, diesel
• 5.7L V8 (350 cu in) — OHV, naturally aspirated, gasoline

Body styles covered

• 4-door crew cab pickup

Trims covered

• Base
• High Sierra
• Sierra Classic

Known issues on the 1989 R2500. The manual's value is the detail it carries on three engines that ask for different service: valve adjustment, fuel delivery or injection specifications, cooling and charging procedures, and the torque values for each. Around them sit the crew cab's brake, suspension, steering and axle sections and the wiring diagrams and diagnostics for its electrical system, which is usually where an intermittent fault is finally run down.