Disassembly; Tools And Shop Equipment; Accessory Removal; Cleaning - GMC 1990 Light Truck Repair Manual

TOOLS AND SHOP EQUIPMENT

A clean, well lit work area should be available. Other
necessary equipment includes: A suitable parts cleaning
tank, compressed air supply, trays to keep parts and
fasteners organized, and an adequate set of hand tools.
An approved engine repair stand will aid the work and
help prevent personal injury or damage to engine
components.
Special tools are illustrated throughout this section, and
are listed at its end. These tools (or their equivalents) are
specially designed to quickly and safely accomplish the
operations for which they are intended. The use of these
tools will also minimize possible damage to engine
components.
Some precision measuring tools are required for
inspection of certain critical components. Torque
wrenches will be necessary for correct assembly of
various parts.

ACCESSORY REMOVAL

This manual assumes that the engine accessories have
been removed. These accessories may include one or
more of the following:
Hydraulic Pump
AIR Pump
Generator
Air Conditioning Compressor

DISASSEMBLY

Cooling Fan
Distributor
Carburetor
TBI Unit
It is beyond the scope of this section to detail the many
different accessory installations. Refer to the proper Truck
Service Manual for this information.
Diagrams of emission and vacuum hose routings,
wiring harness routing, accessory drive belt layout, etc.,
should be made before removing accessories.
Remove the engine accessories before cleaning, to
provide better access to engine exterior surfaces. After
removing the carburetor, TBI unit, distributor, fuel pump,
etc., cover the openings with tape to prevent the entry of
water, solvent and dirt.
Methods used to clean the engine will depend on the
aids which are available. Steam cleaning, pressure
washing, or solvent cleaning are some acceptable
methods. Allow the engine to dry before beginning the
work.
It is important that the engine be as clean as possible to
prevent d irt from e n te rin g c ritic a l areas d uring
disassembly.
♦ i l Remove or Disconnect
□
1. Oil pan plug and allow the oil pan to drain.
2. Oil filter.
3. Block drains and allow the coolant to drain.
+4-
Install or Connect
1. Oil pan plug and washer.
2. Block drain plugs.
• Block drain plugs to 14 N m (10 ft. lbs.).
4-+
Remove or Disconnect
1. Bolts.
2. EGR valve.
3. Gasket.

EXHAUST MANIFOLD REMOVAL

Remove or Disconnect
1. Exhaust manifold bolts, washers, and tab washers.
2. Heat shield (if equipped).
3. Exhaust manifold.
4.3 LITER V-6 6A3-5

CLEANING

DRAINING THE ENGINE

Tighten

EGR VALVE REMOVAL