I cannot emphasize enough how important it is to make sure you never run your Jeep to the point that it is getting too hot ... it can cause all sorts of problems, including ruining your engine. A Jeep that is running too hot may have a bad thermostat, air in the system, a water pump problem, restriction, etc.
Assuming it is the thermostat, here are the Jeep Service Manual steps for thermostat replacement:
1. Disconnect negative battery cable at battery.
2. Drain cooling system.
3. Raise vehicle on hoist.
4. Remove splash shield.
5. Remove lower radiator hose clamp and lower radiator hose at thermostat housing.
6. Remove thermostat housing mounting bolts, thermostat housing and thermostat.
Here's a diagram of the location in a 3.7 engine. The lower radiator hose will connect to the Thermostat housing (1).
Installation instructions:
1. Clean mating areas of timing chain cover and thermostat housing.
2. Install thermostat (spring side down) into recessed machined groove on housing assembly. Make sure
rubber seal locating tab is positioned in the corresponding notch in the housing.
3. Position thermostat housing on timing chain cover.
4. Install two housing-to-timing chain cover bolts. Tighten bolts to 12 N.m (105 in. lbs.) torque.
5. Install lower radiator hose on thermostat housing.
6. Install splash shield.
7. Lower vehicle.
8. Fill cooling system. ***
9. Connect negative battery cable to battery.
10. Start and warm the engine. Check for leaks.
*** Make sure you fill with the proper coolant, and that you properly bleed the system. For model years up to 2010, you will use HOAT Coolant (MOPAR or Zerex G-05) ... for 2011 and later years, you will use OAT coolant.
