Ford 2003 Mustang Workshop Manual page 1902

indicates higher water content than required.
NOTE: The addition of Motorcraft Cooling System Stop Leak Pellets, VC-6,
darkens Motorcraft Premium Gold Engine Coolant from yellow to golden tan.
If Motorcraft Premium Gold Engine Coolant (yellow color) VC-7-A or equivalent
meeting Ford specification WSS-M97B51-A1 has a clear or pale yellow color, this
indicates higher water content than required.
Dark brown can indicate unauthorized stop leak may have been used. Use
Motorcraft Cooling System Stop Leak Pellets VC-6 or equivalent meeting Ford
specification ESE-M99B37-5 except as noted in ES-F65E-19A511-AA only.
A light or reddish brown color indicates that rust may be present in the cooling
system. Flush the system and refill with the correct mixture of water and engine
coolant.
An iridescent sheen on top of the coolant or a milky brown color can indicate a
trace of oil is entering the system. For additional information on engine diagnosis,
refer to
3. If the engine coolant appearance is acceptable, test the engine coolant freezing point
range with the special tool. The freezing point should be in the range -50°F to -10°F. If
the vehicle is driven in cold climates less than -34°F, it may be necessary to increase the
coolant concentration to get adequate freeze protection.
Maximum coolant concentration is 60/40.
Minimum coolant concentration is 40/60.
4. Check the coolant system conditions:
If the intercooler fluid is low, add the specified coolant mixture only.
If the intercooler coolant fluid tests weak, add straight engine coolant until the
readings are within acceptable levels.
If the engine coolant tests strong, remove some of the engine coolant and add
water until readings are within acceptable levels.
5. If the concern remains after the inspection, determine the symptom(s). GO to
6. Verify the cooling system is correctly filled and bled. Refer to
Draining, Filling and Bleeding
Symptom Chart
SYMPTOM CHART
Condition
Loss of intercooler
coolant
Pinpoint Tests
PINPOINT TEST A: LOSS OF COOLANT
Section 303-00 .
in this section.
Possible Sources
Intercooler.
Intercooler
radiator.
Water pump.
Coolant hoses.
Degas bottle.
Symptom Chart
Supercharger Cooling System
Action
Go To Pinpoint Test
A .
.