NOTE: The N14 CELECT™ and CELECT Plus™ engines has one engine coolant thermostat and one aftercooler thermostat. The N14 STC engines have two engine thermostats and no aftercooler thermostat. The artwork in this procedure reflects the N14 CELECT™ engine but is representative of all the engines.

Drain the cooling system. Refer to Procedure 008-018 in Section 8.

NOTE: If the coolant is to be used again, the container must be free of oil and dirt. Before pouring coolant back into the engine, it must be tested for SCA concentration.

Remove the upper radiator hose from the thermostat housing and disconnect the air compressor coolant return line from the thermostat housing.

Remove the capscrews that attach the thermostat housing to the rocker lever housing.

Remove the thermostat housing from the water transfer tube.

Remove the thermostat cover capscrews and disassemble the thermostat housing.

If the thermostat housing assembly is being replaced, remove the coolant temperature sensor from the thermosat housing.

Remove the thermostat from the cover.

Inspect the thermostat seal and the thermostat cover gasket surface. Refer to Procedure 008-016 in Section 8.

NOTE: The N14 CELECT™ and CELECT Plus™ engines has one engine coolant thermostat and one aftercooler thermostat. The N14 STC engines have two engine thermostats and no aftercooler thermostat. The artwork in this procedure reflects the N14 CELECT™ engine but is representative of all the engines.

Install the thermostat into the cover.

Install a new gasket onto the thermostat housing.

Install the thermostat cover and mounting capscrews.

Tighten the capscrews.

Install the coolant temperature sensor into the thermostat housing.

Install the thermostat housing assembly and mounting gasket onto the rocker lever housing and onto the water transfer tube.

Inspect the transfer tube o-ring. Replace if necessary.

Install the mounting capscrews and washers.

Tighten the capscrews.

Install the upper radiator hose and the air compressor coolant return line to the thermostat housing.

Tighten all hose clamps.

Fill the engine with heavy duty coolant. Refer to Procedure 008-018 in Section 8.

Operate the engine and check for leaks.