Isuzu NHR 4J Series, Workshop Manual

Page: 256 / 406

ENGINE COOLING 6B - 13
7. Radiator Assembly
• Remove upward the radiator assembly with hose,
taking care not to damage the radiator core by fan
blade.
INSPECTION
Radiator Valve
• Apply air pressure from filler neck using radiator cap
tester and check the opening pressure of radiator
valve. If the valve opening pressure is out of the
standard value range, replace with a new radiator
valve.
Radiator valve opening pressure kPa (kg/cm
2
/psi)
93 - 123 (0.95 - 1.25/13.5 - 17.8)
• Remove the radiator valve and check a negative
pressure valve as the center of the valve seat side. If
the negative pressure valve does not work smoothly,
clean or replace the radiator valve.
Radiator valve fixing torque N ∙ m (kg ∙ m/lb ft)
6 (0.6/4)
• Conduct cooling system leakage check after
reinstalling the radiator valve.
Radiator Core
• Deformed radiator fins could reduce radiation effects,
resulting in overheat. Straighten the fins. In such a
case, take care not to damage the fin roots.
• Remove dust and other foreign materials.
Flushing the Radiator
• Wash the inside of radiator and the coolant passage
with water and neutral detergent. Remove all scales
and rust.
Checking for Coolant Leakage
• Clog up the reserver tank hose carefully and check the
cooling system for leakage with a radiator cap tester
by applying an air pressure of 147 kPa (1.5 kg/cm
2
/21
psi) from filler neck to inside the radiator.
• As the radiator upper tank is provided with a valve, the
pressure fails to rise higher than the valve opening
pressure unless the hose is clogged up.
6B-12-1.tif