Centinel System – Repair Manual – 007-039   Lubricating Oil Thermostat

WARNING  To reduce the possibility of personal injury, avoid direct contact of hot oil with your skin.

WARNING  Some state and federal agencies have determined that used engine oil can be carcinogenic and cause reproductive toxicity. Avoid inhalation of vapors, ingestion, and prolonged contact with used engine oil. If not reused, dispose of in accordance with local environmental regulations.

Remove the alternator.
Refer to Procedure 013-001 (Alternator) in Section 13.

Remove the water pump.
Refer to Procedure 008-062 (Water Pump) in Section 8.

Remove the thermostat plug.

Remove the tapered snap ring.

Remove the thermostat from the lubricating oil cooler housing.

WARNING  The flash point of new lubricating oil is approximately 221°C [430°F]. Do not allow the oil temperature in the container to exceed 149°C [300°F]. Do not allow water droplets to enter the container of hot oil. Water droplets will cause a violent reaction that can cause personal injury.

Suspend the thermostat and a 127°C [260°F] thermometer in a container of new lubricating oil. Do
not allow the thermostat or the thermometer to touch the sides of the container.

Heat the lubricating oil.

Write down the temperature at which the valve is fully extended. The valve
must be fully extended to at least 6 mm [0.250 in] from the closed position when the temperature reaches 127°C [260°F].

Replace the thermostat if it does
not operate as described.

Inspect the valve for damage. Any damage to the front face of the valve will allow oil to constantly bypass the oil cooler.

If cracks are found on the oil thermostat, inspect the oil cooler housing for the correct seat depth.
Refer to Procedure 007-003 (Lubricating Oil Cooler) in Section 7.

Install the thermostat into lubricating oil cooler housing.

Install the tapered snap ring with the tapered side facing away from the lubricating oil cooler housing.

Install and tighten the thermostat plug.

Install the alternator.
Refer to Procedure 013-001 (Alternator) in Section 13.

Install the water pump.
Refer to Procedure 008-062 (Water Pump) in Section 8.

Prime the lubricating oil system.
Refer to Procedure 007-037 (Lubricating oil System) in Section 7.

Operate the engine to normal operating temperature and check for leaks.