1990 GMC C6000 Topkick Service and Repair Manual
This factory service and repair manual for the 1990 GMC C6000 Topkick covers three engines in a single chassis. Two are naturally aspirated gasoline V8s with overhead valves, the 6.0L of 366 cubic inches and the 7.0L of 427 cubic inches, and the third is a turbocharged 6.6L overhead-valve inline-six diesel of 403 cubic inches. Only one body style is listed, the 2-door conventional cab and chassis, and only one trim code, C6H042. The gasoline and diesel material is kept apart, so specifications and procedures for one engine never bleed into the next.
Engines covered
- 6.0L V8 (366 cu in) — OHV, naturally aspirated, gasoline
- 7.0L V8 (427 cu in) — OHV, naturally aspirated, gasoline
- 6.6L inline-six (403 cu in) — OHV, turbocharged, diesel
Body styles covered
- 2-door cab & chassis, conventional
Trims covered
- C6H042
Known issues on the 1990 C6000 Topkick. The 1990 C6000 Topkick comes back clean on the federal record, with no recalls and no owner complaints recorded. That puts all the value in the service content. Whether the truck has one of the gasoline V8s or the turbocharged 6.6L diesel six, the manual carries its specifications, adjustment and overhaul procedures and torque values, and the conventional cab and chassis around it gets the same system-by-system treatment, with wiring diagrams and diagnostic charts for its circuits.
