Mishimoto Low-Temp Thermostat

1999–2007 Dodge Ram 2500 / 3500 5.9L Diesel

Part #: MMTS-RAM-99L

Overview

The Mishimoto Low-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 1999 through 2007. This thermostat activates at a lower temperature of 180°F, compared to the factory units that typically open at 190°F or 200°F. By allowing coolant to circulate sooner, it helps maintain optimal engine temperatures, reducing the risk of overheating and protecting your engine from costly damage.

Ideal for drivers who frequently tow heavy loads or operate their trucks in warmer climates, this thermostat enhances cooling system reliability under demanding conditions. Backed by Mishimoto’s Lifetime Warranty, it offers durable performance and peace of mind for Cummins-powered Dodge Ram owners seeking a dependable upgrade.

Key Features

Engineered to improve cooling efficiency and safeguard your engine, the Mishimoto Low-Temperature Thermostat includes these key benefits:

• Activates at a lower temperature of 180°F for earlier coolant flow compared to factory thermostats
• Direct-fit design ensures easy installation without any modifications
• Enhances engine temperature regulation during heavy towing and extreme driving conditions
• Compatible with 1999–2007 Dodge Ram 2500 and 3500 models equipped with 5.9L Cummins diesel engines
• Constructed from high-quality materials for long-lasting durability and corrosion resistance
• Helps prevent engine overheating and potential internal damage
• Meets or exceeds OEM specifications for perfect fit and reliable function
• Backed by Mishimoto’s Lifetime Warranty for superior quality assurance

Construction & Design

The Mishimoto Low-Temperature Thermostat is crafted from premium-grade materials designed to endure the rigors of heavy-duty use and high-temperature environments. Its precision-engineered valve reliably opens at a consistent 180°F, ensuring timely coolant flow activation to maintain optimal engine temperatures. The robust construction resists corrosion and wear, providing dependable performance throughout the life of your Dodge Ram. Built to meet or exceed OEM standards, this thermostat guarantees a perfect fit and seamless integration within your truck’s cooling system.

Installation & Fitment

Installation is straightforward thanks to the thermostat’s direct-fit design, which matches the factory unit’s dimensions and mounting points exactly. No modifications or special tools are required, making it an ideal upgrade for both DIY enthusiasts and professional mechanics. This thermostat fits Dodge Ram 2500 and 3500 models from 1999 through 2007 equipped with the 5.9L Cummins diesel engine, ensuring broad compatibility across these popular trucks.

What's Included

• Mishimoto Low-Temperature Thermostat (180°F activation)
• Gasket or O-ring as required for installation
• Installation instructions

Ideal For

This thermostat is perfect for Dodge Ram owners who demand improved cooling system performance, especially those who:

• Operate their trucks in hot or warm climates
• Regularly tow heavy trailers or haul large loads
• Seek to prevent overheating and extend engine life
• Require a reliable, long-lasting replacement for a failing or aging factory thermostat

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.