Here the instructions.
- Take off the plastic cover located near the top of the radiator if present.
- Remove the protective shield located on top of the belt pulling the water pump. You will need to undo two 10mm nuts and one 10mm bolt.
- Undo the 10mm nut that holds water pump housing togeter with the oil dipstick.
- Take off the air intake assembly.
- Move the PCM computer to one side, ensure that the module is safely placed.
- Release the belt tensioner using a big flat screwdriver.
- Remove the serpentine belt from the water pump pulley
- Remove the upper radiator hose. This is held by a metal clamp. Use plyers to remove the clamp.
- Remove also the clamp from the thermostat housing bypass hose, without removing the hose (you have to bleed coolant first).
- Unscrew the four 10mm bolts that hold the water pump housing and letcoolant drain from water pump plug. At this point you can also removethe lower radiator hose to drain faster.
- After coolant drains remove the water pump housing.
- At this point you have to use a special Water Pump removal tool onwater pump cand turn clockwise until the pump is sliding off thehousing.
- Remove the pump and the o-ring located inside the water pump housing.
- Clean and grease the area, put a new o-ring and install back water pump housing
- Install the new water pump using the special tool and following operations in reverse order.
You may need to use sealant tabs from a Cadillac or GM dealer. Here is what you need.
Better going to your local dealer to get the best product for yourCadillac. You will also need a 3/8'' ratchet, socket and extensions
Youmay also need to replace the housing cover gasket. You will need toreplace the O-Ring, that usually comes with the new pump.
When installing new pump you must also ensure that the new pump is aligned correctly,one of the tabs on the pump housing is different and will lock up the pump, so it must bealigned properly while installing.
Here pump:2000 Cadillac DeVille Water Pump
Here the special tool: Water Pump Removal and Installation Impact Socket