SERVICE MANUAL UPDATE-SEC.6E3 CRANK SENSOR REMOVAL/INSTALL

SUBJECT: SERVICE MANUAL UPDATE/SECTION 6E3/REVISED CRANK SENSOR REMOVAL AND INSTALLATION PROCEDURE

VEHICLES AFFECTED: 1991 A/H/N 3300, 3800 ENGINE (VIN C,H)

A new procedure is to be used when removing and installing the dual crank sensor on 1991 vehicles equipped with 3300 (VIN N) and 3800 (VIN C) engines. The harmonic balancer on these engines is now press fit onto the crankshaft and requires the use of Tool J-38197 for removal. The torque specification to be used during installation has also been revised. The procedure to be used when replacing the crank sensor on 1991 3300 (VIN N) and 3800 (VIN C) equipped vehicles is as follows:

REMOVAL:

-------- 1. Disconnect serpentine belt from crankshaft pulley. 2. Raise vehicle on hoist. 3. Remove right front tire and wheel assembly. 4. Remove right inner fender access cover. 5. Using 28 mm socket, remove crankshaft harmonic balancer retaining bolt. 6. Remove crankshaft harmonic balancer using Tool (J 38197). 7. Remove foreign object deflector (Do not use pry bar). 8. Disconnect sensor electrical connector. 9. Remove sensor and pedestal from block face. 10. Remove sensor from pedestal.

INSTALLATION:

------------- 1. Loosely install crankshaft sensor on pedestal. 2. Position sensor with pedestal attached on Tool J 37089, (available through Kent-Moore Tools). 3. Position tool on crankshaft. 4. Install bolts to hold pedestal to block face, torque to 25-35 N.m (18- 26 ft.lbs.). 5. Torque pedestal pinch bolt to 3-5 N.m (26-44 in.lbs.). 6. Remove Tool J 37089. 7. Install foreign object deflector. 8. Place Tool J 37089 on harmonic balancer and turn. If any vans of the harmonic balancer touches the tool, replace the balancer assembly. 9. Install balancer on crankshaft. 10. Apply thread sealer GM #1052080 or equivalent to threads of crankshaft balancer bolt. Torque bolt to 140 N.m + 56 degrees (104 ft. lbs. + 56 degrees). 11. Install inner fender shield. 12. Install tire and wheel assembly. Torque lug nuts to 140 N.m (104 ft. lbs.). 13. Lower vehicle. 14. Install serpentine belt

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.