GMC 4000 Series Service Manual page 267

Sec. 6A
Page 256
GASOLINE ENGINES
1 To Timing Chain
and Sprocket
2 Oil From Camshaft
Front Bearing
3 Rocker Arm Shaft
Bracket
4 Rocker Arms
Figure 2 — Engine Lubrication Diagram for V6 Engine
p asses through oil filter. Oil passages carry oil
under pressure to all crankshaft, camshaft, and
connecting rod bearings. Oil for lubrication of
valve rocker arm s is supplied through passages
C'Moine M aintenance, an d < 1u m -r U ' p .
G M C S E R V I C E M A N U A L
5 Oil From Camshaft
Rear Bearing
6 Oil Galleries
7 Oil Drain-Back Holes
8 Oil Filter
9 Engine Oil Pump
T-3319
Figure 3 — Oil Filter with T hrow -Aw ay Type Element
drilled in block, cylinder heads, and one rocker
arm shaft bracket on each head. From the bracket,
the oil passes into hollow rocker arm shaft and
out through an oil hole to each rocker arm.
ENGINE MAINTENANCE
SERVICING AIR CLEANERS
Carburetor air cleaners on all vehicles re­
quire occasional servicing. For type and location
of air cleaners, recommended element servicing
intervals, and servicing procedures, refer to LU­
BRICATION (SEC. 0) of this manual.
CHECKING AND MAINTAINING
CRANKCASE OIL LEVEL
Daily, or oftener if necessary, check oil level.
Check when at operating temperature, and after
engine has been stopped for at least five minutes.
Remove dipstick, wipe clean, reinsert and remove