2003 Chevrolet Trailblazer EXT Service and Repair Manual

This factory service and repair manual for the 2003 Chevrolet Trailblazer EXT lists two engines and two trims: the 4.2L DOHC inline-six of 256 cubic inches and the 5.3L OHV V8 of 325, both naturally aspirated and gasoline-fueled, in LS or LT form on the four-door sport utility body. A pushrod V8 and a twin-cam six need different procedures at almost every step of engine work, from timing to torque sequence to diagnostic specification, and this manual gives each its own sections instead of a shared summary.

Engines covered

• 4.2L inline-six (256 cu in) — DOHC, naturally aspirated, gasoline
• 5.3L V8 (325 cu in) — OHV, naturally aspirated, gasoline

Body styles covered

• 4-door sport utility

Trims covered

• LS
• LT

Known issues on the 2003 Trailblazer EXT. The federal record holds three recalls for this year. Corrosion from road splash and salt can seize a rear side door latch so it will not latch or unlatch, letting a door open in motion. Heat and vibration can loosen a tail lamp and stop lamp bulb until it flickers out, taking the brake or turn signal with it. Water in the wiper modules can short or corrode them, so the wipers refuse to run or refuse to stop. Complaints reach 1,255, led by 334 on the electrical system and 202 on the fuel system.