Ford 2009 Mustang Owner's Manual page 252

Maintenance and Specifications
2. If the engine oil level is not within the normal range, add only certified
engine oil of the recommended viscosity. Remove the engine oil filler cap
and use a funnel to pour the engine oil into the opening.
3. Recheck the engine oil level. Make sure the oil level is not above the
normal operating range on the engine oil level dipstick.
4. Install the dipstick and ensure it is fully seated.
5. Fully install the engine oil filler cap by turning the filler cap clockwise
1/4 of a turn until three clicks are heard or until the cap is fully seated.
To avoid possible oil loss, DO NOT operate the vehicle with the
engine oil level dipstick and/or the engine oil filler cap removed.
Engine Oil Recommendations
4.0L V6 Engine
Look for this certification
trademark.
Use SAE 5W-30 engine oil
Only use oils "Certified For Gasoline Engines" by the American
Petroleum Institute (API). An oil with this trademark symbol conforms
to the current engine and emission system protection standards and fuel
economy requirements of the International Lubricant Standardization and
Approval Committee (ILSAC), comprised of U.S. and Japanese
automobile manufacturers.
To protect your engine and engine's warranty, use Motorcraft SAE 5W-30
or an equivalent SAE 5W-30 oil meeting Ford specification
WSS-M2C929-A.
Do not use supplemental engine oil additives, cleaners or other engine
treatments. They are unnecessary and could lead to engine damage that
is not covered by Ford warranty.
Change your engine oil according to the appropriate schedule listed in
the scheduled maintenance information.
252
2009 05+ Mustang (197)
Owners Guide
USA (fus)