3512B Petroleum Engines Caterpillar

Illustration 1	g00286378
Test Location (1) Plug.

Check the accuracy of the water temperature indicator or water temperature sensor if either of the conditions that follow are found:

1. A normal temperature is indicated, but the engine is too hot. A loss of coolant is found.

2. A hot temperature is indicated, but there is no loss of coolant.

Remove the plug (1). Install the 4C-6500 Digital Thermometer or the 2F-7112 Thermometer. Also, install the 6B-5072 Terminal Bushing. A temperature indicator of known accuracy can also be used to make this check.

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Personal injury can result from escaping fluid under pressure. If a pressure indication is shown on the indicator, push the release valve in order to relieve pressure before removing any hose from the radiator.

Start and run the engine until the temperature reaches the desired range according to the test thermometer. If necessary, put a cover over part of the radiator and cause a restriction of the coolant flow. The reading on the water temperature indicator should agree with the test thermometer within the tolerance range of the water temperature indicator.

Water Temperature Regulator Test

1. Remove the regulator from the engine.

2. Heat water in a pan until the temperature is 92°C (198°F). Stir the water in the pan. This will distribute the temperature throughout the pan.

3. Hang the water temperature regulator in the pan of water. The water temperature regulator must be below the surface of the water. The water temperature regulator must be away from the sides and the bottom of the pan.

4. Keep the water at the correct temperature for ten minutes.

5. After ten minutes, remove the water temperature regulator. Immediately, check the distance of the opening of the water temperature regulator. The distance must be a minimum of 10.4 mm (.409 inch).

6. If the distance is less than 10.4 mm (.409 inch), make a replacement of the water temperature regulator.