TRUCK SERVICE MANUAL
The intake air system group consists of intake manifolds,
Intake Air System
connections, air cleaners, piping, cold-starting aids, and
turbochargers. The turbochargers are covered in separate
CLEANING AND INSPECTION
6 and 12-volt plugs are not interchangeable.
1. Clean intake manifold or air connection with steam.
2. Inspect for chips, cracks, distortions and damaged
5. Assemble clamp washer (5, Fig. 10-1) and nozzle (2)
threads. Discard unusable parts.
to adapter (6).
3. Damaged threads may be repaired by installing Heli-
6. Tighten nozzle to 15 to 20 ft-lbs [2.1 to 2.8 kg m] and
bend washer over one of hexagonal sides of nozzle.
7. Install assembled adapter in intake manifold.
Due to the lower compression ratio of turbocharged
A pressurized spray can or a rag wet with ether will
engines, they may not start unaided below 50 deg. F [10
usually provide quick starting as low as -10 deg. F [-23
deg. C]. For this reason, the glow plug cold-starting aid
deg. C] . Below this temperature, some means of
is supplied as standard on these engines.
injecting a carbureted ether vapor directly into intake
This aid uses engine fuel which is pressurized by a hand
manifold is necessary.
pump and atomized in a nozzle in the intake system.
atomized spray is ignited by the glowing coil of the glow
plug and provides sufficient heat for combustion of fuel in
Do not attempt to use ether compound type starting
Fuel supply should be obtained from fuel tank. If this is
aids near heat, open flame or on engines equipped
impractical, supply may be taken from pipe plug in center
with glow plug system.
bottom of fuel pump housing or by a connection in engine
fuel supply line. These methods are not desirable due to
allow air to be pulled into engine fuel system.
1. Remove preheater adapter (6, Fig. 10-1) and glow
plug (1) from intake manifold.
2. Remove nozzle (2) and clamping washer (5) from
3. Clean adapter and nozzle with Bendix carburetor
cleaner, or equivalent. Be sure nozzle screen (3, Fig.
10-1) and spray holes are open and clean. Check "O"
ring (4) for damage.
4. Check glow plug on 6-volt or 12-volt source, as
1. Glow Plug
4. "0" Ring
Fig. 10-1, (N21019). Glow plug preheater adapter spray