Overview
The Mishimoto MMTS-WRA-12 is a 180 degree racing thermostat for the 3.6L Pentastar V6 in Jeep Wrangler models. Its low activation temperature lets coolant begin flowing through the cooling system earlier than a stock thermostat, which reduces and maintains lower engine coolant temperatures.
It is suited to rock-crawling use, warm climates, and extreme driving or towing conditions. A faulty thermostat can lead to engine overheating and potential internal damage, and this low-temperature unit helps protect the Pentastar. Each thermostat is built with high-quality wax for reliable, repeatable operation.
Key features
- Opens at 180 degrees F, compared with 203 F for the stock unit
- Low activation temperature lets coolant flow through the system earlier
- Designed for 2 and 4-door models with the 3.6L V6 Pentastar engine
- High-quality wax construction for reliable, repeatable operation
- Suited to warm climates and extreme driving or towing conditions
- Covered by the Mishimoto Lifetime Warranty
Racing thermostat trade-offs
A racing thermostat trades one thing for another. Opening earlier keeps coolant moving sooner, which helps during long grades or hot weather. The cost is that the engine may run cooler than a stock setup, which can affect cabin heat and how the engine management responds. Owners in very cold regions sometimes find the temperature gauge stays low in winter.
Think about how you drive before swapping. A rock-crawling or towing rig that spends time at low speed in warm weather has different needs than a daily driver. If the vehicle already overheats, check the radiator, fan, coolant level and water pump before expecting a thermostat alone to solve it. A thermostat controls flow; it does not add cooling capacity.
When the cooling system is open, inspect the housing, hoses and sealing surfaces, and replace any gasket that is used. Refill with the correct coolant mix, bleed air from the system, and keep an eye on the gauge during the first few drives. Check the coolant level again after the swap.
Specifications
| Brand | Mishimoto |
|---|---|
| Part number | MMTS-WRA-12 |
| UPC | 748354010862 |
| Type | Racing thermostat |
| Temperature rating | 180 degrees F (opening) |
| Stock thermostat opening | 203 F |
| Engine | 3.6L V6 Pentastar |
| Body styles | 2 and 4-door models |
| Construction | High-quality wax |
| Warranty | Mishimoto Lifetime Warranty |
Vehicle fitment
It is designed for the 3.6L V6 Pentastar engine in Jeep Wrangler JK models. Confirm fit for your vehicle’s year, model and trim before ordering.
Confirm fit for your vehicle’s year, model and trim before ordering, especially if you own a TJ, LJ, YJ or other Jeep model.
What’s included
The thermostat is the item supplied, along with the Mishimoto Lifetime Warranty.
