Mishimoto High-Temp Thermostat

1994–1998 Dodge Ram 2500 / 3500 5.9L Cummins Diesel

Part #: MMTS-RAM-94H

Overview

The Mishimoto High-Temperature Thermostat is a precision-engineered, direct-fit replacement designed specifically for Dodge Ram 2500 and Ram 3500 trucks equipped with the 5.9L Cummins diesel engine from 1994 to 1998. This thermostat is engineered to activate at 190°F, which is 10 degrees higher than the factory unit, allowing your engine to reach optimal operating temperature faster. By delaying coolant flow, it improves warm-up efficiency, reduces engine wear during cold starts, and enhances heater performance—especially beneficial in colder climates.

Ideal for owners looking to address common cooling system issues caused by aging or faulty factory thermostats, this upgrade helps prevent engine overheating and potential internal damage. Whether you’re maintaining a classic Ram truck or seeking a reliable cooling system upgrade, the Mishimoto High-Temp Thermostat offers enhanced thermal control and durability for long-lasting performance.

Key Features

This high-temperature thermostat delivers several advantages that improve your Dodge Ram’s cooling system reliability and engine longevity:

• Higher activation temperature of 190°F for faster engine warm-up
• Direct-fit design for easy, no-modification installation
• Durable construction engineered to withstand high temperatures and pressure
• Improves heater efficiency in cold weather conditions
• Helps prevent premature engine wear caused by prolonged cold operation
• Compatible with 5.9L Cummins engines in 1994–1998 Dodge Ram 2500 and 3500 models
• Includes Mishimoto’s Lifetime Warranty for guaranteed quality and reliability

Construction & Design

Crafted with high-quality materials, the Mishimoto thermostat is built to endure the demanding environment of heavy-duty diesel engines. Its robust valve mechanism ensures precise thermal control, while the corrosion-resistant housing maintains consistent performance over time. Designed to meet or exceed OEM specifications, this thermostat offers a reliable upgrade that enhances cooling system efficiency without sacrificing durability.

Installation & Fitment

This thermostat is a direct replacement for the factory unit on 1994–1998 Dodge Ram 2500 and Ram 3500 trucks equipped with the 5.9L Cummins diesel engine. Installation is straightforward and requires no modifications—simply remove the old thermostat and install the Mishimoto unit. This hassle-free upgrade restores optimal cooling system function and improves engine warm-up times, making it an ideal maintenance or performance enhancement part.

What's Included

• Mishimoto High-Temperature Thermostat (190°F activation)
• Gasket or O-ring seal for proper installation
• Installation instructions

Ideal For

This thermostat is perfect for Dodge Ram 2500 and 3500 owners who want to improve the reliability and efficiency of their 5.9L Cummins engine’s cooling system. It is especially beneficial for drivers in colder climates seeking better heater performance and reduced engine wear during cold starts. Enthusiasts maintaining classic Ram trucks, fleet operators requiring dependable cooling components, and anyone aiming to prevent engine overheating and extend engine life will find this thermostat an excellent upgrade choice.

Mishimoto is a performance cooling brand offering aluminum radiators, intercoolers, oil coolers, hoses, and supporting hardware built to manage heat on hard-driven street and track vehicles. For boosted setups and towing/off-road rigs alike, Mishimoto upgrades are designed to increase cooling capacity and reliability where factory systems can become a limitation.