Crankcase and Induction System Leakage Test

Robert Bosch

RPM

Meter No.

Visual

No.

Engine

Speed

3.5

Light Gray

1800

3.2

Light Gray

2000

2.6

Haze

2200

2.4

Clear

2400

( 5 ) Oil level indicator tube flange.

T h e m e t e r readings shall

have

Note.

(6) Oil filler tube flange.

precedence over the visual reading.

(7) Intercylinder preformed hoses.

8-2.

C r a n k c a s e and Induction System

(8) Injector nozzle and holder (at rocker

Leakage Test

arm cover).

a. General. The engine crankcase and in-

(9) Cylinder head oil drain system.

duction systems should be pressure tested to

(10) Fan drive housings.

determine whether or not all connections are

g. Minor Pressure Leakage. Minor leaks

water-tight and airtight. The complete assem-

should be repaired (h, below) during this test

bled engine is air-pressure tested for leaks. Leaks

procedure and rechecked. However, some minor

that are present will be indicated by the

l e a k s are acceptable providing the engine passes

presence of air bubbles when using a soap

the final acceptance test outlined below. Mark

s o l u t i o n on the joints as outlined below.

any area where leaks are evident so that the leak

Seal all openings as

Seal Openings.

may be repaired.

directed in (1) through (3), below.

(1) Reduce air pressure to zero.

(1) Seal exhaust outlet openings on left and

(2) Remove seal (tape) from oil filler and

right turbosuperchargers (fig. 8-2).

indicator tube caps and close caps securely.

( 2 ) Seal air inlet openings in left and right

( 3 ) Pressurize system six inches of mercury

turbosuperchargers (fig. 8-1).

(in. Hg.).

(3) Seal oil filler and indicator tube caps

(4) Test pressure loss after a five-minute

( f i g . 1-2 or 1-7).

( e x p o s u r e ) time interval must not exceed 3-1 / 2

c. Remove Engine Cooling Fans. R e m o v e

inches mercury (in. Hg.).

e n g i n e cooling vanes and cooling fans (fig. 4-34

Repair of Minor Pressure Leakage.

and 4-35). The fans are removed in order to gain

E x a m i n e marked areas (g, above) for loose hose

a c c e s s to several of the points of application of

clamps, loose attaching parts at mounting

the soap solution (f, below).

flanges, defective gaskets, or defective hoses,

d . Install Sleeve Spacer. Install two fan rotor

whichever may exist. Repair leak by replacing

hub sleeve spacers - 4 9 1 0 - 7 9 5 - 7 9 5 2 , t o p r e v e n t

d e f e c t i v e hoses or gaskets or by tightening loose

oil seepage (fig. 4-87 ).

h o s e clamps or loose mounting flange attaching

e. A p p l y A i r P r e s s u r e . I n s t a l l a t e e - t y p e

parts.

c o n n e c t i o n in crankcase breather tube (fig. 1-7).

i. Remove Sleeve Spacer. R e m o v e t w o f a n

Connect manometer and air hose connection in

rotor hub sleeve spacers - 4910-795-7952 (fig. 4-

t e e . Apply air pressure and regulate air pressure

87).

to indicate ten inches of mercury (in. Hg.) on

j . Installation of Cooling Fans. I n s t a l l e n g i n e

manometer.

c o o l i n g fans (fig. 4-35).

f . Apply Soap Solution. A p p l y s o a p s o l u t i o n

k. Check Cooling Fan Clearance. C h e c k f a n

to all locations listed in (1) through (10), below.

blade clearance following instructions which

(1) Air indication system and intake

accompany figure 4-88.

manifolds.

l . Install Cooling Fan Vanes. Install cooling

fan vanes (fig. 4-34).

(2) Exhaust system.

( 3 ) Pipe plugs in crankcase, oil pan, intake

8-3. Fuel and Oil System Leakage Test

manifold, exhaust manifold and crankcase

a . G e n e r a l . This test is made to determine if

damper and oil filter housing.

a n oil or fuel leak exists within the engine "V"

( 4 ) All ventilation and vacuum line fittings.

prior to and in conjunction with engine run-in

This shall include all hose connections.

8-2