TESTING AND ADJUSTING
The 1P5500 Portable Phototach Group is used to
check the fan speed. The testing procedure is in Special
9S9102 THERMISTOR THERMOMETER GROUP
Start the engine. Put a cover over part of the radiator.
1P5500 PORTABLE PHOTOTACH GROUP
The reading on the gauge for water temperature must be
the same as the reading on the thermistor thermometer.
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
Pressure Cap For Radiator
leaks. The pressure needed to make the relief valve in
the pressure cap open is approximately 7 psi (0.49
One cause for a pressure loss in the cooling system
can be a bad seal on the pressure cap of the radiator.
Inspect the pressure cap carefully. Look for damage to
the seal or the sealing surface. Any foreign material or
deposits on the cap, seal or fill neck of the radiator must
9S8140 COOLING SYSTEM PRESSURIZING
SCHEMATIC OF PRESSURE CAP
A. Sealing surface of cap and radiator.
Gauge For Water Temperature
Tools Needed: 9S9102 Thermistor Thermometer
Test procedure for water temperature regulators:
If the engine gets too hot and a loss of coolant is a
1. Remove the regulator from the engine.
problem, a pressure loss in the cooling system can be the
cause. If the gauge for water temperature shows that the
2. Put heat to a pan of water. Get the temperature of
engine is getting too hot, look for coolant leakage. If a
the water to 197° F (92° C).
place can not be found where there is coolant leakage,
check the accuracy of the gauge for water temperature.
3. Hang the regulator in the pan of hot water. Put the
Use the 9S9102 Thermistor Thermometer Group.
regulator completely under the water. Do not let the
regulator make contact with the pan.
CAUTION: Be 'careful when working around an engine if
it is running.