The 12-valve first-gen Cummins in your Ram is considered one of the best diesel engines ever produced, and for good reason. Fuel efficiency, torque, and simplicity are just a few characteristics that give the Cummins its stellar reputation. We're huge fans of the Cummins engine, which is why we’ve developed a high-temperature thermostat for the 1989-1993 5.9L 12v Cummins. This Mishimoto thermostat activates at a higher temperature (189.5°F) compared to the factory thermostat (180°F). By raising the activation temperature, coolant flows through the system later, promoting quicker engine warmup. The Mishimoto high-temperature thermostat is ideal for vehicles in cold climates, where rapid warmup and quicker in-cabin heat is vital. This thermostat includes a high-quality replacement gasket and our signature Mishimoto Lifetime Warranty.

Fitment:
Dodge D250 Base 1989
Dodge D250 Base 1990
Dodge D250 Base 1991
Dodge D250 Base 1992
Dodge D250 Base 1993
Dodge D350 Base 1989
Dodge D350 Base 1990
Dodge D350 Base 1991
Dodge D350 Base 1992
Dodge D350 Base 1993
Dodge W250 Base 1989
Dodge W250 Base 1990
Dodge W250 Base 1991
Dodge W250 Base 1992
Dodge W250 Base 1993
Dodge W350 Base 1989
Dodge W350 Base 1990
Dodge W350 Base 1991
Dodge W350 Base 1992
Dodge W350 Base 1993