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.

Remove the thermostat seal. Do not damage the thermostat cover.

Clean and inspect the thermostat housing for cracks, pitting, or other damage.

Replace if damage is found.

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.

Inspect the thermostat seal for cracks, corrosion, or other damage. Replace if necessary.

CAUTION  When installing a new seal, the flat side of the seal must be toward the mandrel for correct installation.

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.

Use thermostat seal mandrel, Part Number ST-1225, and a lead hammer to install the seal.

A counterbore in the housing bore locates the seal.