Engine Overhaul — Disassembly Sequence (Chevrolet Trailblazer 1)

1. It is much easier to work with the engine and remove components if it is installed on a portable stand. This stand is available for rent. Before securing the engine to the stand, the flywheel/drive plate must be removed.

2. If a stand is not available, parts can be removed from the engine mounted on a support surface. Place wooden blocks under the power unit. Do not allow the engine to tip over.

3. If the engine is to be replaced with a reconditioned power unit, remove and reposition the attachments and external components. These elements include the following:

Generator with brackets
Elements of the exhaust gas control system
Thermostat with casing
Cooling system pump
Elements of the injection system
Intake/Exhaust Manifold
Oil filter
Engine mounts
Drive disk

Note: When removing external components from the engine, take into account all factors that may be useful and important during subsequent assembly. Mark the original positions of gaskets, seals, washers, studs, oil seals, bolts and other small parts.

4. If you plan to purchase a replacement engine, which consists of a cylinder block, crankshaft, pistons and connecting rods as an assembly, remove the cylinder head, oil pan and oil pump from the old engine. Alternative recovery methods are described in the relevant subsection at the beginning of this guide.

5. If the engine is to be restored during a major overhaul, remove the internal components in the following sequence.

Valve cover
Intake and exhaust manifold
Drive chain cover
Pallet
Oil pump
Drive chain and sprockets
Camshaft
Cylinder head
Pistons/connecting rods
Crankshaft rear oil seal housing
Crankshaft and main bearings

6. Before you begin disassembling and repairing the engine, make sure you have the following tools, fixtures and materials. Also, please refer to subsection 11, and prepare the tools and materials needed to assemble the engine.