TM-9-2320-272-23-1

TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)

TECHNICAL MANUAL; FIELD MAINTENANCE MANUAL; VOLUME 1 OF 5

SEPTEMBER 2012

TM-9-2320-272-23-1 - Page 217 of 1313

AIR INTAKE SYSTEM OPERATION

The air intake system channels and cleans air going to the combustion chamber, where it mixes with fuel from the

injectors to provide power for the engine. This system is identical on all models, except where indicated. Major

components of the air intake system are:

A. AIR CLEANER INDICATOR

- Shows red when engine air filter needs servicing.

B. RAIN CAP

- Prevents rain and large objects from entering air intake system.

C. AIR INTAKE EXTENSION TUBE

- Routes air to air intake system. Can be removed for shipping.

D. STACK-TO-AIR INTAKE EXTENSION TUBE

- Routes air to air cleaner and is high enough to keep

intake opening above fording level.

E. STACK-TO-AIR CLEANER ELBOW

- Flexible connection between air stack and air cleaner.

F. AIR CLEANER

- Filters dirt and dust from air.

G. HOSE

- Flexible connection between air cleaner and air cleaner outlet tube.

H. AIR CLEANER OUTLET TUBE

- Routes air from air cleaner to intake manifold.

I. INTAKE MANIFOLD

- Distributes air to combustion chambers in each cylinder head (M939/

A1

series

only).

J. TURBOCHARGER

- Mounts on exhaust manifold and uses spent exhaust gases to drive impeller and

pressurize air entering aftercooler (M939A2 series only).

K. AFTERCOOLER

- Distributes compressed air from turbocharger to combustion chambers while cooling

air intake out of turbocharger (M939A2 series only).

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