The 1999 Dodge Ram 1500 features several different engine models, including the 3.9-, 4.7-, 5.2-, 5.9- and 8.0-liter. The procedure to change the water pump on all the engines is the same. Dodge uses a special tool to remove the constant tension hose clamps. You can find the tool at any Dodge dealership. When changing the water pump, the tension should be checked on all the clamps, and they should be replaced as needed. Be sure to use only clamps with a matching ID number.
Slide the drain pan under the radiator petcock. Remove the radiator cap. Loosen the petcock and allow the coolant to drain. If the drain pan is clean and the coolant is less than five years old, you can reuse the coolant. Unbolt the fan shroud and push it toward the engine, over the fan. Loosen bolts on the front of the fan --- but do not remove --- using the appropriate socket.
Loosen the tension on the accessory drive belt by fitting the appropriate socket over the bolt in the center of the tensioner pulley. Some engines might have a tensioner pulley with a square hole in the center. If so, insert the square end of the ratchet into the hole. Push the pulley toward the engine to loosen tension on the belt. Lift the belt off the pulleys. Allow the tensioner to return to its normal position -- do not let it snap into place; you could damage the tensioner.
Remove the lower and upper radiator hoses, using the clamp removal tool. If your particular engine has a heater hose attached to the water pump, remove the heater hose. Remove the bolts from the front of the fan and lift the fan and shroud out of the engine as an assembly. Remove the four water pump pulley bolts, using the appropriate socket, and remove the pulley. The 4.7-liter engine does not have this type of pulley, so will be handled differently.
Remove the heater hose pipe-mounting bolt, if you removed the heater hose from the water pump. Loosen the bypass hose clamp at the water pump. Remove the seven water pump-mounting bolts. (The 4.7-liter engine doesn't have a bypass hose. And it has one more nut that requires removal in addition to the seven mounting bolts.) The bolts, depending on the engine, might be of different lengths. Be sure to make a notation of the bolts' locations as you remove them.
Clean the gasket-mounting surface on the engine using the rubber scraper and the rags. On all engines, except the 8.0-liter, smear a thin layer of RTV silicone on the water pump's gasket mounting surface. Fit the gasket onto the water pump and press it into the RTV. The 8.0-liter uses an O-ring. Fit the O-ring into its groove.
Coat the water pump bolts with anti-seize. Install the water pump and tighten the bolts to 30 foot-pounds of torque on all engines, except the 4.7-liter. Tighten the bolts to 40 foot-pounds of torque on the 4.7-liter engine.
Coat the threads of the heater hose pipe with sealant. Install the retaining bolt and tighten it to 12 foot-pounds of torque. Reconnect the bypass hose, if you removed it. Spin the water pump impeller to ensure that it does not rub on the timing chain case. Reinstall the water pump pulley and tighten the bolts to 20 foot-pounds of torque.
Reinstall the upper and lower radiator hoses and tighten the clamps using the clamp tool. Slide the fan and fan shroud into the engine compartment as an assembly. Push the shroud toward the engine. Install the fan bolts and tighten them firmly. Pull the fan shroud into place and bolt it onto the radiator. Close the petcock. Refill the radiator. Reinstall the radiator cap.
