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Step 17: Remove the heater pipe from the water pump with a wrench, remember the orientation.
Step 18: Install the heater pipe on the new water pump with some thread sealant
with Teflon with the same orientation it had on the old pump. This will be
pretty self explanatory when you do this. You can always place the pump in front
of its location and check the pipe with the heater hose location.
Step 19: Remove the temperature sensor from the old thermostat housing.
Step 20: Install the temperature sensor in the new thermostat housing with some thread sealant with Teflon.
Step 21: Clean the engine gasket surfaces well with a gasket scraper and a wire
brush. I made sure the surfaces were free of any RTV or previous gasket
material. I cannot stress this enough, take your time on this. You have already
taken the time to take everything off, you really don't want to do this twice do
you? Make sure it is gasket free, failure to do so can result in a leaky
Note: Jeep Forum, Wrangler Forum, etc, there are many conversations on how to gasket prep for the thermostat and water pump. Most people say RTV and you are free to use that. I follow the factory service manual and have not had an issues yet. If you lack an inch-lbs torque wrench RTV might be a good option.
Step 22: The FSM says to install the water pump gasket dry and with the silicone
bead facing the water pump. Install the pump and hand tighten the bolts evenly.
Then torque them in a criss-cross fashion to 23 N•m (200 in. lbs.).
Step 23: Install the thermostat into the engine block with the bleeder hole at the top. Make sure the thermostat is properly seated in the block as it can cause the housing to crack when tightening if it is not. The FSM had two thermostat installation sections I picket the lower torque of the two. I think one covered the 4 cylinder but it was not clear. So this is what I did. I wet the paper gasket with water and had the silicone bead facing the thermostat housing and then installed it. Hand tighten evenly then torque to 20 N•m (15 ft. lbs.). I have done two of these now and having the small torque wrench has been indispensable. No cracked housing, no leaks! Skip using a torque wrench at your own risk.
Step 24: Reconnect the hoses.
Step 25: Reinstall the fan pulley.
Step 26: Reinstall the idle pulley near the alternator and the left of the water pump.
Step 27: Reinstall the serpentine belt. If you have not changed it in a while (ie 2 years or so) or it has cracks and is glazed, this is a good time to replace it and keep your old one as a trail spare.
Step 28: Reinstall the fan and shroud.
Step 29: Reinstall the overflow bottle and hose.
Step 30: Refill the radiator with new fluid. and start the engine with the cap off. Keep filling the radiator until its full as air will continue to burp out making room for more fluid. At this point I shut off the engine and loosened the heater hose at the thermostat to let the air out. Note: The engine was not hot at this point. Once fluid came out I reset the clamp.
Note: The factory clamps are finicky on used hoses, so you may have to shift them around if there are leaks. I did not replace the heater hoses, I need to look into this.
You can test your new install with a Stant Pressure Tester, I got mine of Ebay
for 60 bucks. I needed to find a pesky slow leak on our TJ and this tool was
indispensable. Pumping the radiator up to about 15 lbs, it held the pressure
fine. The cap is rated to 18 lbs and has a spring. If your cap is 5 years old or
so, it will lose some strength and most likely release before 18lbs. Caps are
under 5 bucks, since mine tested out at 14 lbs, I swapped it with a new one
before this build.