Ignition System - Spark Plug Usage Change

87chevy30
GMC NUMBER: 88-T-64

GROUP: 6D - Engine Electrical

DATE: December, 1987

CORPORATE
NUMBER: 836402R
SUBJECT: SPARK PLUG USAGE CHANGE

MODELS: 1988 LIGHT DUTY TRUCKS WITH 4.3L, 5.0L AND 5.7L ENGINES (VIN CODES Z, H AND K)


This bulletin is to advise dealers that there has been a spark plug usage change in production for 1988 trucks with the 4.3L, 5.0L and 5.7L engines. Engines built through August 30, 1987, have spark plugs AC CR43TS, P/N 5614029. Engines built starting August 31, 1987, have spark plugs AC R43TS, P/N 5613325. Due to design differences between the CR43TS and R43TS spark plugs, a radio popping noise may be encountered in vehicles equipped with CR43TS spark plugs. This condition can be repaired by replacing CR43TS spark plugs with R43TS spark plugs. Spark plug gap is 0.035".