Thermostat, Outlet Elbow, Lines, and Fittings

(b) Heat the water slowly while

watching the thermometer and thermostat.

The

thermostat must start to open before the thermometer

indicates 180 F. Replace the thermostat if it fails to

open at 180F or if it opens at too low a temperature.

(4) Inspect the water outlet elbow for cracks,

damaged threads, and distortion; replace a damaged

elbow.

(5) Inspect the hoses for cracks, cuts,

deterioration, brittleness, and other damage; replace

damaged hoses.

(6) Inspect all other parts for cracks,

distortion, and other damage; replace damaged parts.

c. Installation. Installation of the thermostat, outlet

elbow, hoses, and fittings is the reverse of removal.

Refer to figure 4-14. Service the coolant and engine

lubrication systems. After installation, run the engine

until it reaches operating temperature, and check for

leaks. Correct any leaks noted.

Figure 4-16. Reverse-flushing tee engine block.

4-30. Water Pump, Cooling Fan and Fan Belt

a. Fan Belt Adjustment. The fan belt should be

d. Install the thermostat and connect the hoses

tensioned so that it can be deflected approximately 3/4

between the engine and radiator (para 4-29). Start the

inch with thumb pressure at a point midway between

engine and allow to run until the coolant reaches

pulleys at the longest belt span. Adjust belt tension as

operating temperature. Check for coolant leaks and

follows:

correct if any are noted.

(1) Loosen the alternator strap mounting

4-29. Thermostat, Outlet Elbow, Lines, and Fittings

screw (5, fig. 4-18).

a. Removal.

(2) Loosen the adjusting screw (3) on the

(1) Drain the radiator and block (para 2-3f).

adjusting strap (2) and pull the alternator (1) away from

(2) Remove and disassemble the thermostat,

the engine with hand pressure to tighten the fan belt (4).

outlet elbow, lines, and fittings as shown in figure 4-17.

(3) Hold the alternator away from the engine

b. Cleaning, Inspection, and Thermostat Testing.

and tighten the adjusting screw (3). Recheck fan belt

(1) Clean all parts by washing in warm, soapy

tension and readjust if necessary. Tighten the strap

water. Remove any greasy or gummy deposits with a

mounting screw (5) after proper adjustment is made.

cloth dampened with cleaning solvent (fed. spec. P-D-

b. Removal.

680) ; dry thoroughly.

(1) Loosen the adjusting screw (3, fig. 4-18)

(2) Inspect the thermostat for obvious

on the alternator adjusting strap and push the alternator

defects, including ruptured bellows and distortion. If the

toward the engine to loosen fan belt tension. Slip the

valve, when cold, can be pushed off its seat with only

fan belt (4) off the alternator drive pulley and disengage

slight effort, the thermostat is defective and must be

it from the fan and pulley.

replaced.

(2) Remove the four cap screws (1, fig. 4-19)

(3) Check the thermostat operation as

and lock washers (2) that secure the cooling fan (3) to

follows:

the pulley on the water pump; remove the cooling fan.

(a) Hang the thermostat by its frame in

a container of water so that it does not touch the

container. Hang a thermometer in the container to

maintain a check of water temperature.

4-20