{"nhtsa_id":10177929,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2020-08-05","date":"2020-07-10","document_id":"No. 27-20","mfr_campaign":null,"replaces":null,"component":"ENGINE AND ENGINE COOLING:ENGINE:OIL/LUBRICATION","mfr_system":null,"summary":"List of approved C40 engine oils for Classic Porsche vehicles.","document":{"url":"https://static.nhtsa.gov/odi/tsbs/2020/MC-10177929-0001.pdf","alternate_url":"https://static.nhtsa.gov/odi/tsbs/2020/MC-10177929-9999.pdf","confirmed":false},"url":"https://open.wenmarpro.com/bulletins/10177929","components":[{"id":"engine","name":"Engine","parent":null},{"id":"engine-oil","name":"Engine oil and lubrication","parent":"engine"}],"codes":[],"topics":[],"vehicles":[{"make":"PORSCHE","model":"911","year_from":1984,"year_to":1984,"match":"exact","vehicle_ids":["1984_porsche_911"]},{"make":"PORSCHE","model":"928","year_from":1984,"year_to":1984,"match":"exact","vehicle_ids":["1984_porsche_928"]},{"make":"PORSCHE","model":"944","year_from":1984,"year_to":1984,"match":"exact","vehicle_ids":["1984_porsche_944"]}],"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":[]}