Short answer
Ford’s WSS-M2C numbers are Ford engineering material specifications for engine oil. WSS-M2C961-A1 is associated with SAE 5W-30 and WSS-M2C962-A1 with SAE 0W-20 in recent Ford gasoline applications. Each code combines a viscosity grade with Ford requirements on top of the industry API/ILSAC baseline, so the exact code in the owner’s manual is what matters.
How to read a WSS code
WSS stands for Worldwide Standard Specification, Ford’s internal material standard system. The M2C prefix covers engine oils, the number identifies the particular specification and the suffix (A1, B1 and so on) marks its version.
Each oil specification is written around one viscosity grade. Older examples include WSS-M2C945-B1 for 5W-20 and WSS-M2C946-B1 for 5W-30; the A1 series that followed includes WSS-M2C961-A1 (5W-30) and WSS-M2C962-A1 (0W-20).
What the newer A1 specifications add
The recent Ford gasoline specifications start from the API service category and ILSAC certification current when they were written, then add Ford-specific requirements. Ford documents are not freely published, so the exact test list is best confirmed with Ford service information.
A newer WSS number is not automatically a universal replacement for every older one. Ford has assigned different codes to different engines and model years, including newer codes such as WSS-M2C971-A1 that appear in some later documentation.
Where you will see these codes
Ford prints the required specification in the owner’s manual capacities and specifications section, often alongside the viscosity grade and a statement that oils meeting it are recommended. EcoBoost, naturally aspirated V8 and hybrid applications can each call out different codes.
Ford diesel engines and some European-market Ford models use separate specifications altogether, so a gasoline WSS code should not be carried over to them.
Choosing oil for a Ford
Read both the WSS number and the viscosity grade from the manual for your exact engine and model year. Then look for that WSS number on the current product data sheet or label.
If a product lists only the viscosity grade and API service category, it may still be suitable, but it is not a confirmation of the Ford specification. That distinction can matter for warranty records.
Frequently asked questions
Is any 5W-30 oil fine if my Ford calls for WSS-M2C961-A1?
Matching the grade is necessary but not sufficient. Look for an oil whose current data lists the WSS-M2C961-A1 specification.
Does WSS-M2C962-A1 replace older 0W-20 or 5W-20 codes?
Not automatically. Use the code your owner’s manual lists for your engine; Ford assigns specifications by application.
General maintenance information. Always follow your vehicle or equipment manufacturer’s requirements and the current product data. Questions? Email [email protected].
