Ford 2013 MUSTANG Owner's Manual page 238

Unscrew the cap slowly. Any pressure will escape as you unscrew the
cap.
Add prediluted engine coolant meeting the Ford specification. See the
technical specifications chart in theCapacities and Specifications
chapter.
Whenever coolant has been added, the coolant level in the coolant
reservoir should be checked the next few times you drive the vehicle. If
necessary, add enough prediluted engine coolant to bring the coolant
level to the proper level.
Recycled Engine Coolant
Ford Motor Company does NOT recommend the use of recycled engine
coolant since a Ford-approved recycling process is not yet available.
Used engine coolant should be disposed of in an appropriate
manner. Follow your community's regulations and standards for recycling
and disposing of automotive fluids.
Severe Climates
If you drive in extremely cold climates:
• It may be necessary to have a Ford authorized dealer increase the
coolant concentration above 50%.
• A coolant concentration of 60% will provide improved freeze point
protection. Increased engine coolant concentrations above 60% will
decrease the overheat protection characteristics of the engine coolant
and may cause engine damage.
If you drive in extremely hot climates:
• It may be necessary to have a Ford authorized dealer decrease the
coolant concentration to 40%.
• A coolant concentration of 40% will provide improved overheat
protection. Decreased engine coolant concentrations below 40% will
decrease the corrosion and freeze protection characteristics of the
engine coolant and may cause engine damage.
Vehicles driven year-round in non-extreme climates should use
prediluted engine coolant for optimum cooling system and engine
protection.
2013 05+ Mustang (197)
Owners Guide gf, 3rd Printing
USA (fus)
Maintenance 237