GMC 1990 Light Truck Repair Manual page 480

6A4-8 4.8 LITER L6
Figure 7—AIR System Components
DRAINING THE ENGINE
Remove or Disconnect (Figure 5)
— Oil pan drain plug (144). Allow the oil to drain.
— Oil filter (174).
— Block drain plug (131). Allow the coolant to drain.
Install or Connect (Figure 5)
— Oil pan drain plug (144) and washer (143).
Tighten
• Oil pan drain plug (144) to 24 N-m (18 ft. lbs.).
— Block drain plug (31).
Tighten
• Block drain plug (131) to 12.7 N-m (112 in. lbs.).
AIR MANIFOLD AND
INJECTION TUBE REMOVAL
Remove or Disconnect (Figures 7 and 8)
1. Air manifold (182).
• Unscrew the fittings.
• Remove the air manifold.
2. Air injection tubes (183).
• The air injection tubes are a push fit.
• If the air injection tubes will not come out, they
may be easier to remove after the manifolds
(31 and 37) are removed, as described later.
MANIFOLD REMOVAL
The intake and exhaust manifolds are removed as an
assembly. Instructions for separating and replacing the
manifolds are outlined later in this section.
Remove or Disconnect (Figures 4, 9, and 10)
1
. Heat stove (191) if used (figure 9).
• Remove the bolt (190).
182. A ir M a n ifo ld
183. A ir In jectio n Tube
184. Valve
Figure 8—AIR Manifold Installation
190. Screw
191. Heat Stove
192. Bracket
Figure 9—Manifold Heat Stove
V i
30. Nut
34. Clamp
35. Bolt
Figure 10—Manifolds Installed
B-05058
B-05059
30
B-05060