Mishimoto High-Temperature Thermostat

1999–2010 Dodge Ram 3500 5.9L/6.7L Cummins

MMTS-RAM-99H

Overview:

The Mishimoto High-Temperature Thermostat is a premium direct-fit replacement designed specifically for Dodge Ram 3500 trucks equipped with 5.9L and 6.7L Cummins engines from 1999 to 2010. A failing thermostat can cause engine overheating and serious internal damage, compromising your vehicle’s reliability and performance. This thermostat improves your cooling system’s efficiency by activating at a higher temperature than the factory unit, allowing your engine to reach optimal operating temperature faster, especially beneficial in colder climates.

Engineered to meet or exceed OEM specifications, the Mishimoto thermostat ensures consistent temperature regulation, enhancing engine longevity and overall cooling system reliability. It is an ideal upgrade for owners seeking dependable cooling performance and peace of mind backed by Mishimoto’s lifetime warranty.

Key Features:

Designed for durability and precision, the Mishimoto High-Temperature Thermostat offers several advantages over stock units:

• Higher activation temperature of 205°F compared to factory thermostats (190°F for 1999–2010 and 2013 trucks, 200°F for 2010–2012 trucks)
• Promotes quicker engine warm-up by restricting coolant flow longer
• Improves engine efficiency and reduces wear in cold weather conditions
• Direct-fit replacement for easy installation with no modifications required
• Constructed with high-quality materials for long-lasting performance
• Compatible with Dodge Ram 3500 trucks equipped with 5.9L and 6.7L Cummins engines
• Includes Mishimoto Lifetime Warranty for superior product assurance

Construction & Design:

The Mishimoto thermostat is crafted from premium-grade metals and engineered to withstand the high thermal stresses of diesel engine operation. Its robust design ensures reliable valve operation and precise temperature control under demanding conditions. The thermostat’s housing and internal components are corrosion-resistant, providing durability and consistent performance over the life of the vehicle. This attention to quality construction helps maintain optimal engine temperatures, preventing overheating and reducing the risk of costly engine damage.

Installation & Fitment:

This thermostat is a direct-fit replacement for the factory unit on Dodge Ram 3500 models from 1999 through 2010 equipped with 5.9L and 6.7L Cummins engines. Installation is straightforward and requires no special tools or modifications, making it an ideal upgrade for both professional mechanics and DIY enthusiasts. Simply remove the old thermostat and install the Mishimoto unit to restore proper cooling system function and improve engine warm-up times.

What's Included:

• Mishimoto High-Temperature Thermostat (Part # MMTS-RAM-99H)
• Gasket or O-ring as required for proper sealing
• Installation instructions

Ideal For:

This thermostat is perfect for Dodge Ram 3500 owners who want to enhance their engine’s cooling system reliability and efficiency, particularly in colder climates where faster engine warm-up is beneficial. It is also an excellent choice for those replacing a faulty or aging factory thermostat to prevent overheating and maintain optimal engine performance. Whether you use your Ram for heavy-duty work, towing, or daily driving, this Mishimoto thermostat provides dependable temperature control and peace of mind.

Vehicle Applications

• 1999–2003 Dodge Ram 1500 Laramie
• 2002–2003 Dodge Ram 1500 SLT
• 1999–2001 Dodge Ram 1500 Sport
• 1999–2003 Dodge Ram 1500 ST
• 1999–2002 Dodge Ram 2500 Base
• 2007–2010 Dodge Ram 2500 Laramie
• 2007–2010 Dodge Ram 2500 SLT
• 2007–2010 Dodge Ram 2500 ST
• 2008–2010 Dodge Ram 2500 SXT
• 1999–2002 Dodge Ram 3500 Base
• 2007–2010 Dodge Ram 3500 Laramie
• 2007–2010 Dodge Ram 3500 SLT
• 2007 Dodge Ram 3500 Sport
• 2007–2010 Dodge Ram 3500 ST
• 2008–2009 Dodge Ram 3500 SXT
• 2008–2010 Dodge Ram 4500 Laramie
• 2008–2010 Dodge Ram 4500 SLT
• 2008–2010 Dodge Ram 4500 ST
• 2008–2010 Dodge Ram 5500 Laramie

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.