TESTING AND ADJUSTING
Look at the gauge for the exact pressure that
Get the pressure reading on the gauge to 20 kPa
makes the pressure cap open.
(3 psi) more than the pressure on the pressure
Make a comparison of the reading on the gauge
with the correct pressure at which the pressure
Check the radiator for outside leakage.
cap must open.
Check all connections and hoses of the cooling
NOTE: The correct pressure that makes the pressure
system for outside leakage.
cap open is on the pressure cap and is also in the
If you do not see any outside leakage and the
pressure reading on the gauge is still the same
If the pressure cap is bad, install a new pressure
after 5 minutes, the radiator and cooling system
does not have leakage. If the reading on the
gauge goes down and you do not see any
outside leakage, there is leakage on the inside of
Radiator and Cooling System Leak Tests (Systems
the cooling system. Make repairs as necessary.
That Use Pressure Cap)
Water Temperature Gauge Test
9S8140 Cooling System Pressurizing Pump
8T470 Thermistor Thermometer Group or
2F7112 Thermometer and 6B5072 Bushing
To test the radiator and cooling system for leaks,
use the procedure that follows:
DO NOT loosen the filler cap or pressure cap on a
hot engine. Steam or hot coolant can cause severe
After the engine is cool, loosen the pressure cap
to the first stop and let the pressure out of the
cooling system. Then remove the pressure cap.
Make sure the coolant is over the top of the
1. Plug (one on each side of engine).
Put the 9S8140 Cooling System Pressurizing
Check the accuracy of the water temperature
Pump Group on the radiator.
gauge if either of the conditions that follow are found: 1.
The gauge reads normal, but the engine is too hot and a
loss of coolant is found.
The gauge shows that the engine is hot, but no
loss of coolant can be found.
Remove plug (1) [1/2 Std. Pipe Thread] and
install the 8T470 Thermistor Thermometer Group or the
2F7112 Thermometer and 6B5072 Bushing.
temperature gauge of known accuracy can also be used
to make this check.
9S8140 PRESSURIZING PUMP GROUP INSTALLED
ON RADIATOR THAT USES PRESSURE CAP