EngineNoise (Check/Replace Crankshaft Position Sensor). GMC Truck GMC K Sierra

Subject:

Engine Noise (Check/Replace Crankshaft Position Sensor)

Models:

1999 Chevrolet and GMC C/K Models (Silverado and Sierra)

with 4.8 L or 5.3 L V8 Engine (VINs V, T -- RPOs LR4, LM7)

Built within the following VIN breakpoints:

Assembly Plant	Division	Beginning Breakpoint	Ending Breakpoint
Ft. Wayne	Chevrolet	1GCEC14V5XZ164472	1GCEK19V2X7165686
Ft. Wayne	GMC	1GTEC14V7XZ521957	1GTEK14V2XZ522548
Oshawa	Chevrolet	2GCEC19V6X1224406	2GCEK19T8X1226918
Oshawa	GMC	2GTEK19T5X1540333	2GTEK19T9X1541310
Pontiac East	Chevrolet	1GCEK19TXXE191961	1GCEK19V3XE194458
Pontiac East	GMC	1GTEK19T0XE535538	1GTEK19T8XE536565
Pontiac East	GMC	1GTEC14V8XE850061	1GTEC14V5XE851233

Condition

Some customers may comment on a whirling sound from the lower rear side of the engine. This occurs as the engine warms up, between 1500 and 2000 engine RPM. The sound may not be present on a cold engine.

Cause

The crankshaft position sensor may be making contact with the reluctor ring.

Correction

Crankshaft Position Sensor with Shim Washer


(1)	Crankshaft Position Sensor
(2)	Shim Washer
(3)	Crankshaft Position Sensor O-ring
(4)	Crankshaft Position Sensor Bolt

Important: Dealers may encounter a few vehicles, shipped from the vehicle assembly plants, which have a 2nd rubber O-ring installed over the crankshaft position sensor, and a copper shim under the mounting tab.

Remove the crankshaft position sensor (1), and check for witness marks caused by contact with the reluctor ring. Reference the Service Manual procedure as needed.
If no witness marks are evident on the crankshaft position sensor (1):

Important: Do not place an additional shim washer (2) on the crankshaft position sensor (1), if one was not previously installed.

2.1.	Reinstall the original crankshaft position sensor (1) with any O-rings and shims that may have been previously installed.

Tighten
Tighten the mounting bolt (4) to 25 N·m (18 lb ft).

2.2.	Continue with standard diagnostic procedures.

If witness marks are evident on the crankshaft position sensor (1):

•	If a shim washer and/or O-ring had been previously installed:

•	call Technical Assistance for additional instructions.

•	If a shim washer and/or O-ring is not present:

1.	Place a shim washer (2) P/N 12565102 on a new crankshaft position sensor.

2.	Install the new crankshaft position sensor (1) with the mounting bolt (4).

Tighten
Tighten the mounting bolt to 25 N·m (18 lb ft).

3.	Perform the Crank Angle Sensing Error (CASE) re-learn procedure.

4.	With the engine at operating temperature, verify the correction of the noise condition.

Parts Information

Part Number	Description
12565102	Shim, Crankshaft Position Sensor
12560228	Sensor, Crankshaft Position

Parts are currently available from GMSPO.

Warranty Information

For vehicles repaired under warranty, use:

Labor Operation	Description	Labor Time
J4355	Sensor, Crankshaft Position - Replace Add - Diagnosis Time	Use Published Labor Time

Labor Operation

Description

Labor Time

J4355

Sensor, Crankshaft Position - Replace

Add - Diagnosis Time

Use Published Labor Time