{"nhtsa_id":10191070,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2021-05-01","date":"2021-04-19","document_id":"21TS-06","mfr_campaign":null,"replaces":null,"component":"ENGINE AND ENGINE COOLING","mfr_system":null,"summary":"Detroit Technical Service Letter for Gen 5 DD15 Exhaust Valve Adjusting Screw Excessive Wear. Some Detroit Heavy Duty Gen 5 DD15 engines are experiencing exhaust valve bridges that fall out of position while running. The engine may experience conditions such as rough running, misfire, or popping out of the intake. Misfire or exhaust pressure fault codes may also be present. Excessive valve lash caused by a worn rocker arm adjusting screw foot results in the valve bridge falling off the exhaust valves.","document":{"url":"https://static.nhtsa.gov/odi/tsbs/2021/MC-10191070-0001.pdf","alternate_url":"https://static.nhtsa.gov/odi/tsbs/2021/MC-10191070-9999.pdf","confirmed":false},"url":"https://open.wenmarpro.com/bulletins/10191070","components":[{"id":"engine","name":"Engine","parent":null}],"codes":[],"topics":[],"vehicles":[{"make":"FCCC","model":"FCCC","year_from":null,"year_to":null,"match":null,"vehicle_ids":[]},{"make":"FREIGHTLINER","model":"FREIGHTLINER","year_from":null,"year_to":null,"match":"exact","vehicle_ids":[]},{"make":"STERLING","model":"STERLING","year_from":null,"year_to":null,"match":null,"vehicle_ids":[]},{"make":"THOMAS BUILT BUSES","model":"THOMAS BUILT BUSES","year_from":null,"year_to":null,"match":null,"vehicle_ids":[]},{"make":"WESTERN STAR","model":"WESTERN STAR","year_from":null,"year_to":null,"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":[]}