3408 TRUCK ENGINE Caterpillar

Annually

Usage:

(23)Thermostat

The opening temperature of the thermostat (bench test in atmospheric pressure) should be 180°F (82°C). The thermostat should be fully open at approximately 197°F (92°C).

1. Remove the hose clamps (1) and the radiator hose (2) from the thermostat housing (3).

NOTE: There are two thermostats, seals and gaskets that must be changed. There is one located on each side of the engine. The procedure that follows, applies to both thermostats.

2. Remove the thermostat housing (3) from the engine block.

3. Remove the thermostat (4) from the housing (3)

4. Replace the seal located inside the housing (3) and the gasket (5).

5. Install a new thermostat (4) in the thermostat housing (3) and install the thermostat housing (3) on the engine block.

6. Install the radiator hose (2) and tighten the hose clamps (1).

7. Start the engine and inspect for leaks and proper operating temperature.

(24)Starting Aids - Checking Glow Plugs (PC only)

1. Disconnect the wire lead from the glow plug terminal on the HEAT-START switch.

2. Install an ammeter with a capacity of over 75 amps, in a series, between the disconnected lead and the terminal on the HEAT-START switch.

3. Turn HEAT-START switch to HEAT.

4. Observe the ammeter. Each 12 volt glow plug draws approximately 12.5 amperes and each 24 volt glow plug draws approximately 6.5 amperes. The ampere draw of one glow plug multiplied by 8 will be the total ampere draw of the glow plugs in the engine. A low reading indicates one or more defective glow plugs.

5. If a defective glow plug is indicated, disconnect one glow plug lead at a time.

6. Turn switch to the HEAT position. Observe the ammeter. Reconnect the lead.

7. The glow plug that does not change the reading on the ammeter, when the switch is turned on, is the defective glow plug.