When making the checks, put the transmission
control lever in neutral and pull up on the park-
ing brake knob to engage the parking brake.
Make all checks at engine LOW IDLE and on the
side of the radiator opposite the fan. Wear eye
The 6V3121 Multitach Group is used to check the
TESTING AND ADJUSTING
Always stop the engine to inspect the cooling
system. Remove radiator filler cap slowly to
relieve pressure. Hot coolant and steam can
cause personal injury. Let coolant become
cool before it is drained.
Cooling system inhibitor contains alkali; keep
from contact with skin and eyes.
A loss of pressure in the cooling system can be
the cause of low coolant level and an engine that
gets too hot. Inspect the filler cap for damage to
the seal and surfaces to be sealed. Any foreign
material or deposits on the cap or surfaces to be
sealed must be removed.
The 9S8140 Pressurizing Pump can be used to
test the pressure relief valve and for application
of pressure to the cooling system to check for leaks.
Remove adapter (1) from the hose of the pres-
surizing pump. Remove pipe plug from radiator
next to the pressure relief valve. Connect the hose
of the pressurizing pump to the hole the pipe plug
was removed from.
6V3121 MULTITACH GROUP
The 9S8140 Cooling System Pressurizing Pump
Group is used to test pressure caps and pressure relief
valves, and to pressure check the cooling system for
9S8140 PRESSURIZING PUMP
The pressure that makes the pressure relief valve
open is -45 to 55 kPa (6.5 to 8 psi). The vacuum
relief valve opens at 7 kpa (1 psi) with decreasing
9S8140 COOLING SYSTEM PRESSURIZING
Checking Filler Cap and Relief Valve
Tools Needed: 9S8140 Pressurizing Pump