Mishimoto
Reference: MMRT-JL-18
Cooling
Mishimoto Aluminum Expansion Tank – Wrangler JL
The factory plastic expansion tank on a Wrangler JL eventually cracks. The TIG-welded aluminum Mishimoto tank holds more coolant, has baffling to reduce aeration off-camber, and a sight glass for an easy level check. Fits Wrangler JL (2018+) and Gladiator JT (2020+); not for the 392 6.4L. Kit includes the tank, hose clamp, O-ring, and radiator cap, with a Lifetime Warranty.
The factory plastic expansion tank on a Wrangler JL isn't a question of if it fails, but when — according to Mishimoto itself. The TIG-welded aluminum tank is built to solve that problem for good.
Technical specifications
- Material: 3A21 aluminum, TIG-welded
- Capacity: 0.36 gallon (about 1.36 L)
- Weight: 8.00 lb (about 3.63 kg)
- Dimensions: 7.52" height, 7.07" width (about 19.1 x 18 cm)
- Finish: wrinkle black powder coat
- Fitment: Jeep Wrangler JL — 2.0L Turbo, 3.6L V6, 3.0L Turbo diesel (2018+) and Jeep Gladiator JT — 3.6L V6, 3.0L Turbo diesel (2020+)
- Not compatible with the 392 6.4L
- Warranty: Mishimoto Lifetime Warranty
What's included
- Expansion tank
- Worm gear clamp
- O-ring
- Mishimoto radiator cap
Who it's for
This is a good option if your Wrangler JL has enough miles on it that a preventive tank swap makes sense, or if you spend a lot of time off-road and want stable cooling even when the vehicle is heavily off-camber.
Unlike the factory tank, the Mishimoto version holds more coolant, has internal baffling to reduce aeration and sloshing when off-camber, and a sight glass that replaces the factory dipstick — letting you check the level at a glance. Installation is easy, and Mishimoto provides a PDF installation guide.
Why it's worth it
- Durable TIG-welded aluminum construction instead of crack-prone plastic
- More capacity plus baffling to reduce aeration on the trail
- Sight glass for a quick, easy level check
Check whether this tank fits your Jeep's engine — if you're not sure, get in touch and we'll help.
Frequently Asked Questions
Will this tank fit my Wrangler JL?
Yes, it fits Jeep Wrangler JL with the 2.0L Turbo, 3.6L V6, or 3.0L Turbo diesel engine, model year 2018 and newer.
Does it fit the 392 with the 6.4L engine?
No, this tank is not compatible with the 392 6.4L.
Does it also fit the Gladiator?
Yes, it fits Jeep Gladiator JT with the 3.6L V6 or 3.0L Turbo diesel engine, model year 2020 and newer.
What's included in the kit?
Expansion tank, worm gear clamp, O-ring, and a Mishimoto radiator cap.
Is installation difficult?
No, the manufacturer rates it as easy and provides a PDF installation guide.
