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Service bulletin No. 27-20

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.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id10177929
Published by NHTSA2020-08-05
Manufacturer's numberNo. 27-20
Manufacturer's date2020-07-10
NHTSA componentENGINE AND ENGINE COOLING:ENGINE:OIL/LUBRICATION

NHTSA's summary

List of approved C40 engine oils for Classic Porsche vehicles.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Engine, Engine oil and lubrication

Vehicles listed
PORSCHE 9111984
PORSCHE 9281984
PORSCHE 9441984

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Other bulletins for the same vehicles and component
No. 19-232023-10-05. Service bulletin. Manufacturers certificate for an overview of approved Porsche A40 engine oils.
No. 18-232023-10-05. Service bulletin. Manufacturers certificate for an overview of approved Porsche C40 engine oils.
No. 17-232023-10-05. Service bulletin. Manufacturers certificate for an overview of approved Porsche C30 engine oils.
No. 16-232023-10-05. Service bulletin. Manufacturers certificate for an overview of approved Porsche C20 engine oils.
No. 26-202020-08-05. Service bulletin. List of approved C30 engine oils for Porsche classic vehicles.
No. 25-202020-08-05. Service bulletin. List of approved C20 engine oils for classic Porsche vehicles.