Checking Thermostat Watch the temperature gauge periodically during operation. If the engine warms up slowly, the thermostat may be stuck in an open position. If the engine overheats, the thermostatmaybe inoperative and is remaining closed.
NOTE An engine that is not working under load will be slow to warm up to operating temperature. This is due to the large capacity cooling system and is normal. When the engine is under load, however, i~ should warm up reasonably soon.
If the operating temperature fails to maintain the proper level in cold weather, and the thermostat is found to be operating properly, radiator shutters should be used.
Thermostat Replacement Drain the cooling system and remove the hood. Remove the two bolts that hold the housing to the water manifold. Loosen ihe hose clamps on the upper hose. Remove by-pass hose (Spark Ignition Only). The housing can be removed and the thermostat lifted out. ~stall a new gasket when the thermostat is reinstalled.
THERMOSTAT
THERMOSTAT WATER MANIFOLD
WATER MANIFOLD
SPARK IGNITION ENGINE
DIESEL ENGINE
Figure 56
68
