Ford 2003 Mustang Workshop Manual page 1858

3. Remove the pressure cap from the cooling system reservoir and the fill plug from the engine
crossover tube.
4. CAUTION: Do not fill the cooling system through the reservoir only. Coolant will not
enter the engine. Only the reservoir and the radiator will be filled and engine overheating
will occur.
Add coolant into the fill neck on the engine crossover tube until coolant reaches the top of the fill
neck on the cooling system reservoir.
5. Install the cooling system pressure cap on the reservoir.
6. Continue to fill the cooling system at the engine crossover fill neck until full.
7. Install the engine crossover tube fill plug.
8. WARNING: To avoid the possibility of personal injury or damage to the vehicle, do
not operate the engine with the hood open until the fan has been first examined for
possible cracks and separation.
CAUTION: If the engine temperature gauge does not move, coolant level is low in
the engine and must be filled. Stop the engine, allow to cool, and fill the cooling system
as outlined.
Run the engine until the thermostat opens (coolant flowing through the radiator lower hose
becomes hot).
9. Stop the engine and allow to cool.
10. Add coolant to the engine crossover tube fill neck until the cooling system is full.
11. Install the fill plug.
12. Repeat the fill procedure if necessary.
Filling — Mach I
CAUTION: Vehicle cooling systems are filled with Motorcraft Premium Gold Engine
Coolant VC-7-A (in Oregon VC-7-B) or equivalent meeting Ford specification WSS-M97B51-A1
(yellow color). Always fill the cooling system with the same coolant that is present in the
system. Do not mix coolant types.
CAUTION: Engine coolant provides freeze protection, boil protection, cooling efficiency,
and corrosion protection to the engine and cooling components. In order to obtain these
protections, the engine coolant must be maintained at the correct concentration and fluid level
in the degas bottle.
When adding engine coolant, use a 50/50 mixture of engine coolant and deionized water.
To maintain the integrity of the coolant and the cooling system:
Add Motorcraft Premium Gold Engine Coolant VC-7-A (in Oregon VC-7-B) or equivalent
meeting Ford specification WSS-M97B51-A1 (yellow color). Use the same coolant that