The thermostat in your Cummins diesel engine allows it to sustain optimal operating temperature for a majority of the time. Without a well-performing thermostat your truck may run poorly, produce excess emissions, or overheat while towing (a common problem in the Cummins 12 valve). To avoid this it is best to replace the thermostat whenever symptoms of wear and poor performance are present, or as directed by your truck's owner's manual.
Instructions
- 1
Place a large, empty fluid container under the drainage plug on the bottom of the radiator.
2Open the radiator cap at the top. Then open the drainage plug at the bottom.
3Remove the section of hosing that leads out of the radiator and into the metal elbow that bolts into the engine block.
4Remove the three bolts that attach the metal elbow to the engine block. Then remove this piece to expose the old thermostat.
5Extract the old thermostat and discard it.
6Clean the thermostat housing thoroughly with a clean terrycloth towel.
7Put the new thermostat into the thermostat housing.
8Place some high temperature silicone sealant around the base of the metal elbow in a circle and bolt it back into place.
9Reattach the hose to the metal elbow and the radiator.
10Screw the drainage plug back into place.
11Refill the radiator with coolant and screw the radiator cap back on.
12Turn on the engine and let it run until it reaches the normal operating temperature.
13Let it cool. Then open the radiator cap and top off the fluid level.