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'05 Water Pump Replacement

By Mike Forbes

Note:  This maintenance write-up for an '05 LJ water pump swap is provided courtesy of Mike Forbes.  Mike was doing some work on his 2005 TJ and asked if I wanted to put the info on the site.  Since I had a water pump write-up for the early TJ 4.0L engines but not for the later years, I was happy to accept his offer.  So here it is, direct from Mike.   And Mike....thanks again for providing this info for everyone else to use.


This is a water pump and high flow thermostat housing install on 2005 LJ.  Procedure is the same for a 4.0 L TJ.  Note this was done along with the timing chain so some of the pictures may show the alternator off its bracket and the radiator missing, this is covered in the timing chain write-up so don't let that throw you.

I purchased the Mopar parts from moparonlineparts.com at the time 31% off list.

Hardware Needed:
Mopar Water Pump and gasket (this is a high flow stock for 2005)
Hesco High Flow Thermostat housing and gasket (High Flow Thermostat Housing #HFTH from http://www.hesco.us/)
Hesco High Flow Thermostat (HP GM/FORD/AMC/JEEP Thermostat 195 degree #4365 from http://www.hesco.us/ )
Mopar Upper Radiator Hose
Mopar Lower Radiator Hose
Thread Sealant with Teflon
NO RTV Required

Serpentine Belt
Heater Hoses

Tools Needed: (I used all metric here, no guarantee some of these aren't standard)
Factory Service Manual (FSM) used for torque settings, below are from an '05, your mileage may vary, verify with a FSM.
1/2" Breaker Bar
Inch lbs Torque Wrench
Middle Range Torque Wrench
11mm socket
13mm socket
14mm socket
Gasket Scraper
Wire Brush
Channel Locks
Large Crescent

Stant Pressure Tester

Since I was changing the timing chain it made sense to replace the water pump and thermostat.  The vehicle is at 97,000 miles and we only got it at 91,000 so I did not know about previous maintenance.  At this time I am also replacing the radiator hoses and thermostat.  Heater hoses are going to happen later and they looked ok.  Make sure you check where they run along the engine block to make sure they are not worn.

The FSM states you need to move the power steering pump, it was not in the way. I left it alone.


I chose to go with a Hesco High Flow thermostat and Housing.  Now I am an upper radiator hose short, Chrysler is apparently back ordered on the upper hose and no ETA.  (I will change it when it becomes available.)


Only sealant needed is for the the temp sensor on the thermostat and the pipe on the water pump.  Picked this up at NAPA.


Step 1: Drain the cooling system.  Using a bucket under the radiator and open the drain valve.


Step 2: Remove the radiator overflow tank by pressing in on the nub inside the shroud and lift up.  Remove the hose from the radiator neck.


Step 3: Once drained, break the fan free with a large crescent wrench.  A big one is needed here as the fan nut is 36mm.

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