Under Valve Cover Leak Test; Cylinder Head Isolation - International VT 275 V6 Manual

DIAGNOSTIC TESTS

Cylinder Head Isolation

• If an air leak is heard, but the location
cannot be detected, isolate each bank,
one at a time, and test. To test the left
bank, remove the left bank rear port plug
and install the ICP Leak Test Plug
(ZTSE4690) in place of the port plug.
Leave the valve covers off, but connect the
ICP sensor. Crank the engine while
measuring ICP pressure. If the engine
starts or ICP pressure exceeds 500 psi,
the leak causing the low ICP is in the
left bank.
• To test the right bank, install the ICP
Sensor Adapter (ZTSE4690) in place of
the rear right bank port plug. Install the ICP
sensor in the top of the adapter and
connect the ICP sensor to the harness
using the three-wire Pressure Sensor
Breakout Harness (ZTSE4347) as an ex-
tension, if needed. Leave the valve covers
off. Crank the engine while measuring ICP
pressure. If the engine starts or ICP
pressure exceeds 500 psi, the leak
causing the low ICP is in the right bank.
98

Under Valve Cover Leak Test

• If the IPR function test reveals a massive
air leak, remove the valve covers and apply
shop air pressure to the ICP System Test
Adapter (ZTSE4594). Attempt to isolate
the location of the leak. The possible leak
points are:
-Rail to injector O-rings
-Rail fittings
-Case-to-head tube and port plug O-rings
-Branch tube assembly
-Pump housing
• If the air leak is in the valve cover area, use
a short length of rubber hose as a
stethoscope to locate the air leak.
• If the air leak is from the crankcase (not the
valve cover area), remove the case-to-head
tubes and inspect the lower O-rings. If the
O-rings are good, remove the high-
pressure pump cover and listen for the air
leak at the pump-to-branch tube connections.
I I C C P P L L E E A A K K T T E E S S T T P P L L U U G G
International ® VT 275 V6 Engine
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