1988 GMC K2500 Service and Repair Manual
This factory service and repair manual for the 1988 GMC K2500 works from a trim list of Sierra, Sierra SLE and Sierra SLX and two cab choices, the standard cab pickup and the extended cab pickup. Four engines are covered: the 5.0L V8, the 4.3L V6 and the 5.7L V8 on gasoline, and the 6.2L V8 on diesel. Each is an overhead-valve, naturally aspirated design, and each gets its own specifications, torque values and diagnostic routines rather than a shared summary.
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 K2500. Four recalls sit on the federal record for this truck, and three are worth spelling out. Replacement fuel filters sold for these trucks may not seal at the connection, letting fuel escape toward any ignition source nearby. Transmission fluid can be forced out of the vent tube when the transmission runs hotter than expected, and it will burn if it lands somewhere hot. An electrical fault can disable rear-wheel antilock braking without lighting the warning lamp meant to tell the driver. One owner complaint, on the electrical system, is logged with NHTSA. Wiring diagrams and brake, fuel and transmission diagnostics answer to all of it.
REAR WHEEL ANTILOCK BRAKE (RWAL) FEATURE COULD BECOME DISABLED BY AN ELECTRICAL MALFUNCTION.
BRAKE WARNING INDICATOR LAMP ON INSTRUMENT PANEL WILLNOT LIGHT TO INFORM THE DRIVER OF RWAL DISABLEM
INSTALL A JUMPER WIRE HARNESS BETWEEN THE TRANSMISSION CONNECTION AND ENGINE WIRE HARNESS.
WHILE DRIVING, EXPERIENCED ERRATIC OPERATION OF VEHICLE, PULLED TO SIDE, FOUND ENGINE COMPARTMENT ON FIRE, DUE TO ALTERNATOR MALFUNCTIONING. *AK
