My 1998 Ford Crown Victoria Police Interceptor recently developed a squeaking sound in a couple of the engine accessories. Squealing sound was intermittent and not always present when the engine was running, volume of the sound also varied. For a 1998 police interceptor, the vehicle in question is low mileage with a little under 80,000 miles on the odometer. But since this vehicle was a fully marked unit at one point in time, it's unknown how many hours the engine idled without accumulating any mileage on the odometer.

Tools Required:

1/2" Drive Ratchet
1/2" Drive 6-point socket set
1/2" Drive Breaker Bar
Flat pry bar
Low profile container with at least 2 gallons capacity

Parts Required:

Water Pump
Antifreeze (optional, can reuse old coolant)

Procedure:

WARNING: Do not attempt water pump replacement while engine coolant is still hot from driving. Let vehicle's coolant temperature fall to a safe temperature before attempting water pump replacement or coolant removal.
 

For the ?? 2000 model year ??, the accessory belt routing changed to reduce the change of the belt becoming detached from the engine during hard acceleration.
 

Item #	Description
1	Alternator
2	Water Pump Pulley
3	Power Steering Pump Pulley
4	Crankshaft Pulley
5	Air Conditioner Compressor
6	Drive Belt
7	Drive Belt Tensioner
8	Belt Idler Pulley

Loosen, but do not remove the 4 bolts that hold the water pump pulley to the water pump. Note, you'll want to grip the back of the water pump pulley with your hand so it does not spin while attempting to loosen the bolts.

If you have a 1999 or later crown vic, the pulley on the alternator will be larger than the 1998 pulley pictured below to reduce belt slippage during hard acceleration. But as a result of the pulley size change, 1999 crown vics do not output as much current (amps) at low idle speeds as 1998 crown vics do.

Remove Serpentine Belt:

In the picture below, the component on the left is the belt tensioner. The component in the middle is the idler pulley (#8 in diagram above). The component on the far right is the waterpump (#2 in the diagram above). A note of intrest, both the idler pulley and the pulley attached to the belt tensioner have the same ford part number stamped into them.

Belt tensioner replacement is straight forward, first remove the serpentine belt then remove the three bolts that hold the tensioner to the engine front cover, slide old tensioner from engine and reassemble. Idler Pulley replacement is likewise straight forward, first remove serpentine belt and then remove the single bolt in the center of the pulley, slide pulley from engine and then reassemble.

To relieve tension on the serpentine belt, insert a 1/2" breaker bar into the square hole of the tensioner above the black wheel. Then twist and tension should be relieved on the serpentine belt. Once tension is relieved, slide the serpentine belt off the alternator pulley and water pump.

Now fully remove the 4 bolts that hold the pulley to the water pump and slide the waterpump pulley off the waterpump

Place suitable low profile container under waterpump area to contain coolant that will leak out when pump is removed.

Remove the 4 bolts that hold the water pump to the engine block, then slide the old water pump out of the engine block. There are 2 metal tabs on the top of the water pump under which a flat prybar can be placed if the water pump does not want to slide out of the block easily.

Place large O-Ring around the new water pump and slide the new pump into place. Insert and tighten 4 bolts that retain pump to engine block.

The circular hole that is drilled into the top of the water pump is the "weep hole". If coolant is leaking from this hole, it means that the internal seals of the water pump have failed and the pump should be replaced. Have seen numerous backyard mechanics attempt to stop leaks here by putting a screw or bolt in this hole. Leak from this hole is an indicator of a problem, not the cause of the problem.

Place pulley on water pump and insert retaining bolts

Relieve tension on the automatic belt tensioner and then place the serpentine belt back over all the accessories. Carefully inspect accessory pulleys to make sure that belt is aligned properly. (Pay very close attention to the alignment of the belt on the a/c compressor).

Finishing Steps:

Replace coolant that leaked out during water pump replacement.
Clean any coolant that leaked onto serpentine belt off (ethylene glycol is very slippery)
Start engine and inspect for leaks.
Turn on high draw accessories such as winsheild defroster and headlights. Observe voltage guage and light brightness closely. If there is there is any coolant left on the belt, the belt will slip around the alternator pulley and the alternator will not charge as a result.

Approximate Costs for Project:
 

Water Pump	$45
Belt Tensioner Assembly	$55
Idler Pulley	$20

(More parts were replaced than absolutely necessary to quiet the squealing noise, but this precaution will likely prevent problems from occuring in the future.)