{"nhtsa_id":54134,"type":"service_bulletin","type_name":"Service bulletin","date_added":"1998-03-30","date":"1997-12-28","document_id":"97122800197","mfr_campaign":null,"replaces":null,"component":"ENGINE AND ENGINE COOLING","mfr_system":null,"summary":"VEHICLES MAY EXPERIENCE A THUMP NOISE FROM THE HEATER CORE THAT MAY BE ACCOMPANIED BY EXCESSIVE TEMPERATURE GAUGE FLUCTUATION. *YC","document":null,"url":"https://open.wenmarpro.com/bulletins/54134","components":[{"id":"engine","name":"Engine","parent":null}],"codes":[],"topics":[],"vehicles":[{"make":"MAZDA","model":"B-SERIES TRUCK","year_from":1994,"year_to":1997,"match":"base","vehicle_ids":["1994_mazda_b-series","1995_mazda_b-series","1996_mazda_b-series","1997_mazda_b-series"]},{"make":"MAZDA","model":"NAVAJO","year_from":1994,"year_to":1994,"match":"exact","vehicle_ids":["1994_mazda_navajo"]}],"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":[]}