{"nhtsa_id":39271,"type":"service_bulletin","type_name":"Service bulletin","date_added":"1995-11-01","date":"1995-02-01","document_id":"CAMP/95C18","mfr_campaign":null,"replaces":null,"component":"ENGINE AND ENGINE COOLING:ENGINE; SERVICE BRAKES, HYDRAULIC:FOUNDATION COMPONENTS","mfr_system":null,"summary":"GENERAL MOTORS HAS DETERMINED THAT CERTAIN 1990-1995 C5H, C6H AND C7H TRUCKS EQUIPPED WITH 6.0L ENGINES (RPO LSO-VIN CODE \"P\") AND AUTOMATIC TRANSMISSIONS MAY EXPERIENCE PREMATURE PISTON FAILURES DUE TO PRE-IGNITION SPARK PLUG FIRING. TO CORRECT THIS CONDITION A NEW DISTRIBUTOR CAP, NEW SPARK PLUG WIRES AND NEW SPARK PLUG WIRE SHIELDS SHOULD BE REPLACED. ON AFFECTED 1995 VEHICLES, ONLY A NEW DISTRIBUTOR ROTOR IS REQUIRED. *TW","document":null,"url":"https://open.wenmarpro.com/bulletins/39271","components":[{"id":"brakes","name":"Brakes","parent":null},{"id":"engine","name":"Engine","parent":null}],"codes":[],"topics":[],"vehicles":[{"make":"CHEVROLET","model":"C SERIES(MEDIUM)","year_from":1990,"year_to":1995,"match":null,"vehicle_ids":[]},{"make":"GMC","model":"C SERIES(MEDIUM)","year_from":1990,"year_to":1991,"match":null,"vehicle_ids":[]},{"make":"GMC","model":"C SERIES(MEDIUM)","year_from":1993,"year_to":1995,"match":null,"vehicle_ids":[]}],"as_of":"2026-10-19","note":"A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.","attribution":[]}