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 (189.5F) compared to the factory thermostat (180F). 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.
This Part Fits:
| Year |
Make |
Model |
Submodel |
| 1989-1993 |
Dodge |
D250 |
Base |
| 1989-1993 |
Dodge |
D350 |
Base |
| 1989-1993 |
Dodge |
W250 |
Base |
| 1989-1993 |
Dodge |
W350 |
Base |
⚠️ California Proposition 65 Warning:
This product may expose you to chemicals known to the State of California
to cause cancer or reproductive harm.
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Fitment guides and tools are helpful, but your car is unique! Some trims and options aren’t always listed, so if you want 100% confidence that a part will fit, our team is happy to double check for you. We take the guesswork out of your purchase by standing behind our expertise.
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Our Promise:
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When we confirm a fitment in writing and it doesn’t work for your application, we cover the return shipping and exchange it at no cost to you.
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