Temperature Regulator

COOLING STSTEM

TESTING AND ADJUSTING

The 1P5500 Portable Phototach Group is used to

check the fan speed. The testing procedure is in Special

Instruction (GMG00819).

9S9102 THERMISTOR THERMOMETER GROUP

INSTALLED

(Typical Example)

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

Pressure Cap For Radiator

valves, and to pressure check the cooling system for

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

kg/cm2).

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

be removed.

9S8140 COOLING SYSTEM PRESSURIZING

PUMP GROUP

SCHEMATIC OF PRESSURE CAP

A. Sealing surface of cap and radiator.

Gauge For Water Temperature

Temperature Regulator

Tools Needed: 9S9102 Thermistor Thermometer

Group.

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 197F (92C).

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.