Belt-driven pump on front of block. Weep hole drip or noisy bearing means replacement. About 2 hours; coolant drain required.
The 4.0L water pump bolts to the front of the timing cover and is driven by the serpentine belt (or V-belts on Renix). It has a weep hole on the bottom that drips coolant when the internal seal fails - look for crusty coolant residue on the bottom of the pump housing. A failing bearing produces a growling or whirring noise that changes with engine RPM. Replacement: drain coolant from radiator petcock, remove serpentine belt, remove fan and shroud (10mm bolts), remove water pump pulley (four bolts), unbolt the water pump from the timing cover (four bolts + the long bolt that also holds the alternator bracket on some years). Mopar 33002990 / Gates 42274 are standard replacements ($30-50). Always use a new gasket; some pumps come with a paper gasket, others require RTV (Mopar Gasket Maker). Torque pump bolts to 22 ft-lb in a crisscross pattern. Refill with 50/50 coolant mix and burp the system per the coolant flush procedure. Replace the thermostat at the same time - it is a $10 part and the housing is already off.
| Part | Vendor | Est. price |
|---|---|---|
| Water pump Gates | RockAuto | ~$50 |
| Thermostat | auto parts | ~$12 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.