Disassembly Of The Engine; Tools And Shop Equipment; Accessory Removal; Cleaning - GMC 1989 Light Duty Truck Repair Manual

6A1-4 2.5 LITER L4 ENGINE
1. Outer Engine Heat Stove
2. Bolt
3. Stud
4. Stud
5. Exhaust Manifold
6. Inner Engine Heat Stove
7. Exhaust Manifold Gasket
8. Stud
9. Bolt
10. Coolant Fitting
11. Gasket
12. Thermostat
13. Thermostat Housing
14. Bolt
15. Hose Clamp
16. Hose

TOOLS AND SHOP EQUIPMENT

A clean, well lit work area should be available. Other
necessary aids include: 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 com ­
partments.
Special tool 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 com ­
ponents.
Some precision measuring tools are required for in­
spection 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
Generator
Distributor
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 routings, accessory drive belt layout, etc.,
should be made before removing accessories.

DISASSEMBLY OF THE ENGINE

17. Cylinder Head Gasket
18. Intake Valve
19. Exhaust Valve
20. Plug
21. Gasket
22. Coolant Temperature Sensor
24. Cylinder Head
25. Cylinder Head Bolt
26. Spark Plug
27. Cylinder Head Bolt
28. Valve Spring Cap
29. Valve Stem Oil Seal
30. Valve Keys
31. Rocker Arm Ball Bolt
32. Rocker Arm Ball
33. Valve Rocker Arm
Figure 2—Cylinder Head, Manifolds, and Components
Cooling Fan
TBI Unit
34. Valve Stem Oil Shield
35. Valve Spring
36. Intake Valve Stem Seal
37. Washer
38. Intake Manifold Bolt
39. Plug
41. Plug
42. Intake Manifold Stud
43. Intake Manifold
44. Intake Manifold Gasket
45. Push Rod Guide
46. Cylinder Head Bolt
47. Push Rod
48. Rocker Arm Cover

CLEANING

Remove the engine accessories before cleaning to
provide better access to engine exterior surfaces. After
removing the TBI unit, distributor, fuel pump, oil filter, 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 w hich are available. Steam cleaning, pressure
w ashing, or solvent clea nin g are som e accep tab le
methods. Allow the engine to dry before beginning the
work.
It is important that the engine be as clean as possible to
p re v e n t d ir t fro m e n te rin g c r it ic a l a re a s d u rin g
disassembly.

PARTS IDENTIFICATION

Refer to figure 2 through 5.

DRAINING THE ENGINE

|<-+| R em ove or D isconnect (Figure 5)
• Oil drain plug (73). Allow the oil to drain.
• Oil filter.
-►4- Install or C onnect (Figure 5)
1. Oil drain plug (73).
Tighten
• Oil pan drain plug to 34 N-m (25 ft. lbs.).
F-01980