Mishimoto · New
Mishimoto 89-93 Dodge 5.9L Cummins 79C High-Temperature Thermostat
MPN MMTS-RAM-89L · Store SKU misMMTS-RAM-89L
Supplier stock checked 11/7/2026, 10:00:22 PM UTC. Adding a part does not reserve it.
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Product details
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 low-temperature thermostat for the 1989-1993 5.9L 12v Cummins. This Mishimoto thermostat activates at a lower temperature (174.2F) compared to the factory thermostat (180F). By lowering the activation temperature, coolant flows through the radiator earlier, maintaining lower fluid temperatures. The Mishimoto low-temperature thermostat is ideal for vehicles in warmer climates, or for use in vehicles experiencing extreme driving/towing conditions. This thermostat includes a high-quality replacement gasket and our signature Mishimoto Lifetime Warranty. Engine coolant thermostat designed to regulate coolant flow and maintain optimal operating temperature. Ensures efficient warm-up, prevents overheating, and supports reliable performance with a precise fit. Thermostat, Low-Temp, fits Dodge 5.9L First-Gen Cummins 1989-1993
Manufacturer fitment & guides
Check MMTS-RAM-89L against the manufacturer’s application information below.
Part-specific notes
- California Proposition 65: Y
