Ford Mustang (1999-2004) Service Manual: Inspection and Verification

WARNING: Never remove the pressure relief cap while the engine is operating or when the cooling system is hot. Failure to follow these instructions can result in damage to the cooling system or engine or personal injury. To avoid having scalding hot coolant or steam blow out of the degas bottle when removing the pressure relief cap, wait until the engine has cooled, then wrap a thick cloth around the pressure relief cap and turn it slowly. Step back while the pressure is released from the cooling system. When you are sure all the pressure has been released, (still with a cloth) turn and remove the pressure relief cap.

CAUTION: Check the coolant and engine oil levels. Top off the coolant level if needed. If there is engine coolant in the engine oil, the cause must be corrected and the oil changed or major component damage can occur.

CAUTION: Some vehicle cooling systems are filled with Motorcraft Premium Engine Coolant VC-4-A (in Oregon VC-5, in Canada CXC-10) or equivalent meeting Ford specification ESE-M97B44-A (green color). Others are filled with Motorcraft Premium Gold Engine Coolant VC-7-A 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.

NOTE: The addition of Motorcraft Cooling System Stop Leak Pellets, VC-6, darkens Motorcraft Premium Gold Engine Coolant from yellow to golden tan.

1. Verify the customer's concern by operating the engine to duplicate the condition.

2. Inspect to determine if any of the following mechanical or electrical concerns apply.

Visual Inspection Chart

3. If the inspection reveals an obvious concern that can be readily identified, repair it as necessary.

4. Inspect the coolant condition.

1. WARNING: Never remove the pressure relief cap while the engine is operating or when the cooling system is hot. Failure to follow these instructions can result in damage to the cooling system or engine or personal injury. To avoid having scalding hot coolant or steam blow out of the degas bottle when removing the pressure relief cap, wait until the engine has cooled, then wrap a thick cloth around the pressure relief cap and turn it slowly. Step back while the pressure is released from the cooling system. When you are sure all the pressure has been released, (still with a cloth) turn and remove the pressure relief cap.

Allow the engine to cool. Once pressure is released, remove the pressure relief cap.

2. CAUTION: Check the coolant and engine oil level and top off the coolant if needed. If there is engine coolant in the engine oil the cause must be corrected and oil/fluid changed or major component damage can occur.

CAUTION: Some vehicle cooling systems are filled with Motorcraft Premium Engine Coolant VC-4-A (in Oregon VC-5, in Canada CXC-10) or equivalent meeting Ford specification ESE-M97B44-A (green color). Others are filled with Motorcraft Premium Gold Engine Coolant VC-7-A 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.

Inspect the coolant color:

• If Motorcraft Premium Engine Coolant (green color) VC-4-A or equivalent meeting Ford specification ESE-M97B44-A has a clear, light green or blue color, this 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 Section.

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 -50F to -10F. If the vehicle is driven in cold climates less than -34F, 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 Symptom Chart .

6. Verify the cooling system is correctly filled and bled. Refer to Supercharger Cooling System Draining, Filling and Bleeding in this section.

Symptom Chart

Pinpoint Tests

PINPOINT TEST A: LOSS OF COOLANT