1988 GMC C2500 Service and Repair Manual

This factory service and repair manual for the 1988 GMC C2500 covers four engines, the 4.3L V6, the 5.0L and 5.7L gasoline V8s and the 6.2L diesel V8, in a truck built as a two-door standard cab or a two-door extended cab pickup. Sierra, Sierra SLE and Sierra SLX are the trims. The extended cab brings its own body, glass and interior procedures, while the engine, driveline and chassis sections apply to both cabs, each with the specifications and torque values that belong to it.

Engines covered

• 5.0L V8 (305 cu in) — OHV, naturally aspirated, gasoline
• 6.2L V8 (379 cu in) — OHV, naturally aspirated, diesel
• 4.3L V6 (262 cu in) — OHV, naturally aspirated, gasoline
• 5.7L V8 (350 cu in) — OHV, naturally aspirated, gasoline

Body styles covered

• 2-door standard cab pickup
• 2-door extended cab pickup

Trims covered

• Sierra
• Sierra SLE
• Sierra SLX

Known issues on the 1988 C2500. Three recalls are on the federal record for this model year. One describes replacement oil filters that could seal inadequately and let engine oil escape, with fire the possible result. A second involves transmission heat beyond what the design anticipated forcing fluid out of the vent tube, where it can ignite. The third concerns rear-wheel antilock braking that an electrical malfunction could disable without the warning lamp lighting to tell the driver. Two owner complaints, both on the suspension, complete the record. Lubrication, transmission and brake diagnostics are all covered here.