On the DT-body Ram 1500 the water pump job is straightforward on the gas engines and a major job on the diesel. The 5.7L Hemi and 3.6L Pentastar both hang the pump on the front of the block where the serpentine belt drives it, so the work is draining coolant, getting the fan and belt out of the way, pulling the pulley, and swapping the pump on a fresh gasket. Access is tight but nothing exotic is needed beyond a good belt tensioner tool and a long extension.
Two things trip people up. First, on eTorque trucks the belt drives a 48-volt motor generator — you have to shut down and disconnect the 48V system, not just the 12V battery, before the belt comes off. Second, loosen the four water pump pulley bolts while the pump is still bolted to the block; once the pump is loose there is nothing to hold the pulley against and you will fight it. Also fill only with Mopar OAT purple coolant and burp the system properly, because trapped air causes a false overheat that gets blamed on the new pump.
| Item | Type | |
|---|---|---|
| Socket set, metric 8, 10, 13, 15, 16, 18 mm 6-point, 3/8 in drive Covers fan shroud, belt tensioner, pulley, pump bolts and battery terminals. | Required | shop |
| Ratchet and extensions 3/8 in drive, 3 in / 6 in / 10 in plus swivel Reaches pump bolts behind the pulley and fan shroud. | Required | shop |
| Insulated gloves and 48V lockout knowledge Class 0 insulating gloves (eTorque only) eTorque trucks carry a 48-volt battery pack; the belt drives a motor generator. | Safety | shop |
| Battery terminal wrench 10 mm socket or wrench Disconnects the 12V negative terminal (and the 48V pack connector on eTorque). | Required | shop |
| Drain pan 8+ quart capacity Catches roughly 3 gallons of coolant from the radiator drain. | Required | shop |
| Serpentine belt tool Long-handle belt tool with 1/2 in drive and 13/15/16 mm crowfoot adapters Releases the automatic tensioner in the tight space behind the fan. | Required | shop |
| Breaker bar 1/2 in drive, 18-24 in Gives leverage on the tensioner and holds the pulley while loosening bolts. | Required | shop |
| Hose clamp pliers Constant-tension spring clamp pliers, cable type Factory spring clamps on the heater and bypass hoses are hard to squeeze by hand. | Recommended | shop |
| Pick and scraper set Plastic/nylon scraper plus O-ring pick Cleans old gasket material off the aluminum sealing face without gouging it. | Required | shop |
| Torque wrench 3/8 in drive, 10-80 ft-lb Pump and pulley bolts thread into aluminum and must be torqued evenly. | Required | shop |
| Fan clutch wrench set 36 mm plus pulley holding tool (only if mechanical fan fitted) Some configurations use a clutch fan that must come off for pump access. | Recommended | shop |
| Torx/hex bit socket set T20-T50 and 5-10 mm hex, 3/8 in drive Some shroud, splash shield and EcoDiesel cover fasteners are Torx or hex. | Recommended | shop |
| Spill-free coolant funnel Universal radiator neck kit with adapters The DT cooling system traps air; a burp funnel is the reliable way to fill it. | Required | shop |
| Timing belt tool kit / camshaft locking tools 3.0L EcoDiesel VM Motori set Diesel pump is timing-belt driven; cam/crank must be locked and belt retimed. | Required | shop |
| Water pump Mopar or OE-equivalent for your engine (Hemi kit includes gasket) The replacement pump; always fit the new gasket or O-ring supplied. | Parts | shop |
| Coolant Mopar OAT MS-90032 (purple/violet), 10-year, 2 gal premix OAT coolant only; mixing with HOAT orange gels the system. | Consumables | shop |
| Serpentine belt Engine/eTorque specific — replace if cracked or over 60k miles The belt is already off; a worn belt will slip on a new pump. | Parts | shop |
| Distilled water 1 gallon For flushing and topping off concentrate; never use tap water. | Consumables | shop |
| Jack and jack stands 3 ton stands, 2.5 ton+ jack Needed to reach the radiator drain and lower splash shield. | Safety | shop |
| Safety glasses Coolant spray and debris around the fan area. | Safety | shop |
5.7L Hemi (eTorque or not): belt-driven pump with 13 mm pulley and mounting bolts, 21 ft-lb. 3.6L Pentastar: also belt-driven off the front cover but with smaller 8/10 mm-head fasteners and an O-ring style seal — torque is lower, verify in the manual. 3.0L EcoDiesel: pump sits behind the front cover and is driven by the timing belt, so it needs the VM Motori cam/crank locking tools and a new timing belt kit.
| 5.7L Hemi water pump to block bolts | 21 ft-lb (28 Nm) |
| 5.7L Hemi water pump pulley bolts | 21 ft-lb (28 Nm) |
| 3.6L Pentastar water pump bolts | verify in the service manual |
| 3.0L EcoDiesel water pump bolts | verify in the service manual |
| Belt tensioner mounting bolt | verify in the service manual |
| Thermostat housing bolts | verify in the service manual |
| Fan shroud fasteners | Hand tight, approx 50-70 in-lb (verify in the service manual) |
The 5.7L Hemi bolt sizes (13 mm pump and pulley bolts) and its 21 ft-lb torque are solid; Pentastar and EcoDiesel fastener torques and the exact fan type on your build vary, so confirm against the FCA/Stellantis service manual for your VIN.
Plan on about 3 gallons (roughly 12-13 quarts) of premixed Mopar OAT purple coolant for the 5.7L Hemi; the 3.6L holds a bit less. Buy 3 gallons of 50/50 premix so you have extra to top off after burping.
Yes. The belt starter generator is part of the serpentine belt drive on eTorque trucks, so disconnect the 12V negative and then de-energize the 48V pack per the service manual before removing the belt. Skipping it risks the BSG moving the belt or a high-voltage shock.
Both the four pulley bolts and the pump-to-block bolts take a 13 mm socket, and both torque to 21 ft-lb (28 Nm). Keep the bolts in order — several lengths are used.
Yes, the 3.0L EcoDiesel pump is behind the front cover and driven by the timing belt, so it requires locking the engine at TDC with the proper tool set. Because the belt has to come off anyway, always install a new timing belt, tensioner and idlers at the same time.