{"nhtsa_id":607315,"type":"service_bulletin","type_name":"Service bulletin","date_added":"1999-09-20","date":"1999-07-01","document_id":"990602013","mfr_campaign":null,"replaces":null,"component":"ENGINE AND ENGINE COOLING:ENGINE:GASOLINE","mfr_system":null,"summary":"SOME OWNERS / OPERATORS MAY COMMENT ABOUT WHITE SMOKE AT COLD IDLE, INADEQUATE CAB HEAT / DEFROST TEMPERATURE IN COLD WEATHER CONDITIONS. *TT","document":null,"url":"https://open.wenmarpro.com/bulletins/607315","components":[{"id":"engine","name":"Engine","parent":null}],"codes":[],"topics":[],"vehicles":[{"make":"CHEVROLET","model":"6H","year_from":1990,"year_to":1999,"match":null,"vehicle_ids":[]},{"make":"CHEVROLET","model":"7H","year_from":1990,"year_to":1999,"match":null,"vehicle_ids":[]},{"make":"CHEVROLET","model":"7T SCHOOL BUS","year_from":1990,"year_to":1999,"match":null,"vehicle_ids":[]},{"make":"GMC","model":"6H","year_from":1990,"year_to":1999,"match":null,"vehicle_ids":[]},{"make":"GMC","model":"7H","year_from":1990,"year_to":1999,"match":null,"vehicle_ids":[]},{"make":"GMC","model":"7T SCHOOL BUS","year_from":1990,"year_to":1999,"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":[]}