How to Install a 1994 Buick LeSabre 3.8 Liter Crank Shaft Sensor

The Buick LeSabre once rivaled the Corvette as one of the longest-running production passenger-car model in the U.S.; it lasted for an impressive 46 years. Its elimination after the 2005 model year took it out of that race, likely the only race against the Corvette that the LeSabre had a chance of winning. The 1994 LeSabres 170-horsepower, 3.8-liter engine used a crankshaft position sensor to measure the speed of the crankshaft's rotation in order to correctly adjust the ignition timing. Installing a new crankshaft position sensor in this engine requires a special tool to remove the harmonic balancer.

Instructions

Removal

1

Draw a diagram of how the serpentine belt routes over all of the pulleys on the engine. Place a ratchet and 18 mm socket on the bolt in the center of the tensioner pulley, located between the alternator and power steering pump, and rotate the ratchet and socket counterclockwise. Hold the ratchet and socket in this position to relieve tension from the serpentine belt.

2

Pull the serpentine belt from all of the pulleys. Allow the tensioner to rotate clockwise slowly until it reaches its resting position. Remove the ratchet and socket.

3

Loosen the lug nuts on the passengers front wheel using a ratchet and socket. Lift the front of the LeSabre with a floor jack and slide jack stands under the vehicles subframe. Lower the Buick onto the jack stands. Remove the lug nuts and pull the wheel from the vehicle.

4

Remove the nine push-pin-style retainers from the wheel-well liner by prying the center pin on each retainer outward with a flat-head screwdriver until it stops moving, then prying each retainer out of the liner. Remove the wheel-well liner.

5

Remove the crankshaft harmonic balancer bolt with a ratchet and 28 mm socket. Connect a harmonic balancer puller, General Motors tool No. J38197, to the harmonic balancer by hand-threading the three small bolts on the puller into the three bolt holes in the harmonic balancer and tightening the center bolt on the puller until it contacts the end of the crankshaft on which the harmonic balance rides.

6

Tighten the center bolt of the harmonic balancer puller with a ratchet and socket until the harmonic balancer pops free from the crankshaft. Remove the harmonic balancer.

7

Remove the four bolts securing the crankshaft position sensor shield using a ratchet and socket, then remove the shield. Press and hold the unlocking button on the crankshaft position sensors wiring harness, then unplug the wiring harness.

8

Unfasten the two bolts securing the crankshaft position sensor to the engine block using a ratchet and deep-well socket, then remove the sensor.

Installation

9

Position a new crankshaft position sensor onto the engine block and hand-tighten its retaining bolts. Tighten the crankshaft position sensor bolts to between 14 and 28 foot-pounds using a torque wrench and deep-well socket.

10

Set the crankshaft position sensor shield back into place on the engine block and hand-tighten its bolts. Snug the sensors bolts with a ratchet and socket. Plug the wiring harness into the new crankshaft position sensors receptacle.

11

Place the harmonic balancer back on the end of the crankshaft. Apply a thin coat of a thread-locking chemical meeting GM specification 1052080 and allow the thread-locking chemical to cure for the amount of time specified by the chemicals instructions. Thread the harmonic balancers retaining bolt by hand. Tighten the harmonic balancers bolt to 110 foot-pounds with a torque wrench and 28 mm socket, then tighten it an additional quarter-turn.

12

Reinstall the wheel-well liner and press all nine of its push-pin-style retainers into the holes in the liner. Press the center pin on each of the retainers inward to lock them into place.

13

Set the wheel back onto the front hub and hand-thread the lug nuts. Raise the LeSabre off the jack stands with a floor jack and lower the vehicle to the ground. Tighten the lug nuts in a crisscrossing pattern to 104 foot-pounds using a torque wrench and socket.

14

Inspect the serpentine belt for any defects, including fraying, slits, cracks, glazing or excessive age. If any defects exist, replace the belt with a new one.

15

Route the serpentine belt around all of the pulleys on the engine except the tensioner pulley, using your diagram as a guide. Rotate the tensioner pulley counterclockwise with a ratchet and 18 mm socket. Line up the belt with the tensioner pulley and allow the tensioner to rotate clockwise slowly until the tensioner seats on the belt.