ENGINE DIAGNOSTIC TEST PROCEDURES
Section 6
•
CRANKCASE PRESSURE
400 Series On-Highway
(with Robert Bosch MW Pumps)
FROM FORM NO. CGED-365
CRANKCASE PRESSURE*
11
A.
LATE MODEL TURBO WITH VALVE COVER MOUNTED BREATHER:
1.Measure @ breather tube with orifice restrictor tool, SE-4039.
2.Measure - High idle (no load) RPM.
INSTRUMENT
GUIDELINE DATA‚
1st CHECK
2nd CHECK
WATER MANOMETER
OR MAGNAHELIC
GAUGE
*Engine must be at normal operating temperature.
p Refer to "Performance Data Guidelines", in this Section.
1.
Measure
crankcase
pressure,
using
breather
restrictor tool SE-4039, as follows: (See Figure 24).
a.
Park vehicle on level ground.
b.
Insure breather tube and element are free of
dirt.
c.
Insure engine oil level is not above full mark.
d.
Connect a line from the restrictor tool to a water
manometer or magnehelic gauge (SE2239).
e.
Run engine at high idle (no load) RPM.
f.
Test must be made with engine specified oil
and water temperatures as shown in the
PERFORMANCE DATA GUIDELINES, at the
end of this section.
g.
Record crankcase pressure in 1st check box on
Form CGED-365.
h.
Crankcase pressure guidelines are as follows:
•T/DTI-466C . . . . .5.5 in. H20 (max.)
IMPORTANT
DO NOT PLUG THE BREATHER TUBE
DURING THE CRANKCASE PRESSURE TEST
AS RESTRICTING THE TUBE CAN CAUSE
CRANKSHAFT
AND
TURBOCHARGER
SEALS TO LEAK.
2.
Excessive crankcase pressure with oil consumption
trend data indicates:
a.
Badly worn or broken rings and/or
b.
Badly worn or scored cylinder sleeves.
3.
Review the recorded results of the crankcase
pressure test. If there is any difference between the
guideline data and the 1st check box, correct as
necessary and repeat the test.
4.
If results obtained during the above tests are within
guidelines, engine operation is satisfactory.
Figure 24. Crankcase Pressure Test
CG ES-240-4
Printed in United States of America
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