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Mishimoto

Mishimoto 89-93 Dodge 5.9L Cummins 87.5C High-Temperature Thermostat

$74.00 $64.95 Save $9.05

SKU: M00C MMTS-RAM-89H

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Non-Returnable Item
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Description

Part #: MMTS-RAM-89H

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.

Features:

  • Direct fit for 1989-1993 Dodge Ram with 5.9L Cummins
  • Higher activation temperature restricts coolant circulation for a longer time, providing quicker engine warmup
  • Ideal for cold climates
  • Includes thermostat and high-quality replacement gasket
  • 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.

MIA's Description

The Mishimoto High-Temperature Thermostat is designed for 1989-1993 Dodge Ram models equipped with the 5.9L Cummins engine. This thermostat activates at a higher temperature of 189.5°F, compared to the OEM's 180°F. By delaying coolant circulation, it promotes quicker engine warmup.

Fitment

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Specifications

BrandMishimoto
Part NumberM00C MMTS-RAM-89H

Buy with Confidence

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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