How to Replace the Voltage Regulator in a 1998 Mercury Mountaineer

In 1997, Ford lent its Explorer platform to the Mercury division of Ford Motor Co. and cre4ated the Mountaineer. The 1998 Mercury Mountaineer came standard with a 205-horsepower, 4.0-liter V-6 engine. The alternator used the rotational power of the engine to create the roughly 14 volts of electricity the Mountaineer required to power the vehicles electronics and keep the battery charged. When the alternators voltage regulator fails, your Mountaineer's electrical system may experience huge spikes and valleys in voltage, which can severely damage electrical components. To replace the regulator, you must remove the alternator, so it is best to replace the alternator altogether, as a replacement alternator comes fitted with a new voltage regulator.

Instructions

Alternator Removal

1

Install a memory saver to the vehicle according to the memory savers instruction manual. Loosen the negative battery cable end with a combination wrench, then disconnect the negative battery cable from the battery. Move the cable aside to prevent accidental reconnection.

2

Loosen the hose clamps on both ends of the air filter box-to-throttle body tube, using a flat-head screwdriver. Pull the crankcase vent tube, the smaller rubber tube, from its inlet on the air filter box-to-throttle body tube.

3

Find the intake air temperature sensor on the air filter box-to-throttle body tube; it is the only electrical component on the tube. Unplug the IAT sensors wiring harness. Pull the air filter box-to-throttle body tube from the throttle body and air filter box inlets and remove the tube from the engine compartment.

4

Draw a diagram of how the serpentine belt routes over all of the accessory pulleys on the front of the engine. Place a breaker bar and socket on the bolt on the belt tensioner and rotate the breaker bar counterclockwise to relieve tension from the belt. Pull the belt from all of the pulleys and slowly allow the tensioner to rotate back to its resting position.

5

Inspect the serpentine belt for any defects, including missing chunks or rubber, severe glazing or fraying. If any defects are present, replace the serpentine belt with a new one. Small cracks in the grooved side of the belt are a part of normal wear and do not mean the belt needs replaced.

6

Unplug the wiring harness from the rear of the alternator. Pull the rubber cover from the alternators battery wire and remove the nut securing the battery wire, using a ratchet and socket. Disconnect the battery wire from its stud on the alternator.

7

Pry the pushpin retainer securing the wiring cluster to the generators bracket, by prying it upward with a flat-head screwdriver. Position the wiring aside.

8

Remove the alternator retaining stud bolt and two bolts, using a ratchet and socket. Lift the alternator from the engine compartment carefully.

Alternator Installation

9

Lower the new alternator into place on the engine and hand-thread the alternator-retaining stud-bolt and bolts. Torque the alternator bolts to between 30 and 40 foot-pounds and the stud-bolt to between 11 and 16 foot-pounds, using a torque wrench and socket.

10

Align the pushpin retainer on the wiring cluster with its mounting hole in the alternators bracket. Press the pushpin downward to insert it into the hole and secure the wiring.

11

Guide the battery wire onto its stud on the rear of the alternator. Hand-thread the wires retaining nut, then torque it to between 80 and 106 inch-pounds, using an inch-pound torque wrench and socket. Position the rubber cover over the end of the battery wire. Plug the wiring harness into its receptacle on the new alternator.

12

Guide the serpentine belt over all of the pulleys on the front of the engine except the tensioner pulley, using the diagram you drew as a guide for how to route the belt. Rotate the tensioner pulley counterclockwise with a breaker bar and socket, then align the belt with the tensioner pulley.

13

Allow the tensioner to rotate clockwise until it contacts the belt and holds tension on it. Remove the breaker bar and socket.

14

Press the air filter box-to-throttle body tube back onto the inlets on the throttle body and air filter box, then tighten its hose clamps to between 28 and 38 inch-pounds. Plug the crankcase vent hose back into its inlet on the tube and plug the IAT wiring harness back into the IAT sensor.

15

Reconnect the negative battery cable and tighten the negative cable ends pinch bolt to between 62 and 89 inch-pounds.