Overview
The Mishimoto MMTS-WRA-87L is a 180 degree racing thermostat for 1987 to 2006 Jeep Wrangler YJ and TJ models with 2.5L 4-cylinder or 4.0L six-cylinder engines. It opens at 180 F, compared with 195 F for standard thermostats, which lets coolant flow through the engine sooner once it is fully warm.
Mishimoto says cooler running reduces engine wear and improves reliability. The thermostat uses high-quality wax, and it carries the Mishimoto Lifetime Warranty.
Key features
- Opens at 180 F, compared with 195 F for standard thermostats
- Wax thermostat for repeatable operation
- Covers 2.5L 4-cylinder and 4.0L 6-cylinder engines
- Mishimoto Lifetime Warranty included
Keeping the cooling system balanced
The thermostat is a small valve that decides when coolant leaves the engine for the radiator. On a YJ or TJ, a thermostat that sticks closed causes quick overheating, while one stuck open keeps the engine cool and can make the heater slow to warm. Wax-type units like this one respond to coolant temperature, so they open gradually rather than all at once.
If you own a TJ or YJ with a 2.5L four or 4.0L six, check the water pump, radiator cap and hoses when you replace the thermostat. These parts are often original and wear alongside the thermostat. A cracked hose or weak cap can cause the same symptoms as a bad thermostat, so check them before assuming the thermostat is the cause.
Install the new thermostat with the spring side facing the engine, clean the sealing faces thoroughly, and bleed air from the cooling system afterward. Watch the gauge on the first few drives and recheck the coolant level once the engine has cooled.
Specifications
| Brand | Mishimoto |
|---|---|
| Part number | MMTS-WRA-87L |
| UPC | 748666007598 |
| Opening temperature | 180 F |
| Standard thermostat | 195 F |
| Engine | 2.5L 4-cylinder and 4.0L 6-cylinder |
| Construction | High-quality wax |
| Warranty | Lifetime |
Vehicle fitment
It fits 1987 to 1995 Jeep Wrangler YJ and 1997 to 2006 Wrangler TJ models. Confirm fit for your vehicle’s year, model and trim before ordering.
Wrangler LJ, JK and JL models are outside the YJ and TJ generations named here, even where the years overlap. Confirm your vehicle’s year, model and trim before ordering.
What’s included
The thermostat is the item supplied. Check the package contents against your installation before starting, including any gasket or hardware you may need.
