Mishimoto MMRT-JL-18 Aluminum Coolant Expansion Tank for 2018+ Jeep Wrangler JL and 2020+ Gladiator JT

Upgrade your Jeep Wrangler JL or Gladiator JT with an aluminum expansion tank built to withstand the toughest trails and daily driving. The stock plastic tanks in Wranglers are known for cracking and leaking at the seams. It is not a matter of if it will fail, but when. Replacing it with this TIG-welded aluminum tank ensures you are ready for your next adventure without worrying about coolant loss.--This coolant recovery tank increases fluid capacity over the factory design and features internal OEM-style baffling to prevent aeration and sloshing when your Jeep is off-camber or bouncing through rough terrain. The wrinkle black powder-coated finish not only adds corrosion resistance but also gives your engine bay a rugged, refined look. An easy-to-read sight glass replaces the factory dipstick, making fluid checks quick and straightforward.--Installation is simple and can be done before your next weekend trip, giving you peace of mind on and off the trail. Complete with a Mishimoto radiator cap and backed by our lifetime warranty, this aluminum expansion tank is the reliable upgrade every Wrangler and Gladiator owner needs. Engine coolant reservoir designed to store and regulate excess coolant for proper system operation. Durable construction resists heat and pressure, helping prevent leaks and maintain optimal temperature.

• Increased coolant capacity compared to stock for better cooling capabilities
• Internal baffling reduces aeration and fluid slosh during rough off-roading
• TIG-welded aluminum construction for maximum strength and reliability

Upgrade your 2018 and newer Jeep Wrangler JL or 2020 and newer Jeep Gladiator JT with the Mishimoto MMRT-JL-18 aluminum coolant expansion tank. Designed for 2.0L, 3.6L, and 3.0L engines, this durable replacement addresses a common weakness of factory plastic reservoirs, which can crack or leak at the seams. TIG-welded aluminum construction provides improved strength and resistance to the heat and pressure of demanding trail use and daily driving, helping protect against coolant loss.
The Mishimoto MMRT-JL-18 increases coolant capacity over the stock design to support reliable cooling system operation. Internal OEM-style baffling helps reduce aeration and fluid slosh when your Jeep is traveling over rough terrain, climbing steep grades, or operating at an angle. A wrinkle black powder-coated finish adds corrosion resistance while providing a clean, rugged appearance in the engine bay. The integrated sight glass replaces the factory dipstick, making coolant level checks fast and easy.
Installation is designed to be straightforward, allowing you to replace the factory reservoir before your next off-road trip or routine service. This kit includes a Mishimoto radiator cap for a complete installation and is backed by Mishimoto's lifetime warranty. Built specifically for Jeep Wrangler JL and Gladiator JT applications, the MMRT-JL-18 is a dependable cooling system upgrade for drivers who demand durability on and off the trail.

• Increased coolant capacity compared to stock for improved cooling system support


• Internal OEM-style baffling reduces aeration and coolant slosh during off-road driving


• TIG-welded aluminum construction provides strength and resistance to heat and pressure


• Wrinkle black powder-coated finish enhances corrosion resistance and appearance


• Integrated sight glass allows quick and convenient coolant level checks


• Includes a Mishimoto radiator cap and is backed by a lifetime warranty

Features:

• Increased coolant capacity compared to stock for improved cooling system support

• Internal OEM-style baffling reduces aeration and coolant slosh during off-road driving

• TIG-welded aluminum construction provides strength and resistance to heat and pressure

• Wrinkle black powder-coated finish enhances corrosion resistance and appearance

• Integrated sight glass allows quick and convenient coolant level checks

• Includes a Mishimoto radiator cap and is backed by a lifetime warranty

Compatible With
2018 Jeep Wrangler
2019 Jeep Wrangler
2020 Jeep Gladiator
2020 Jeep Wrangler
2021 Jeep Gladiator
2021 Jeep Wrangler
2022 Jeep Gladiator
2022 Jeep Wrangler
2023 Jeep Gladiator
2023 Jeep Wrangler
2024 Jeep Gladiator
2024 Jeep Wrangler
2025 Jeep Gladiator
2025 Jeep Wrangler
2026 Jeep Gladiator
2026 Jeep Wrangler