Ford F150 Pickup. Instruction - part 994

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. 

Fig. 6: Engine Cooling System Visual Inspection Chart 
Courtesy of FORD MOTOR CO. 

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

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, turn and remove the 
pressure relief cap (still with a cloth).

CAUTION: Check the coolant level, engine oil and transmission fluid, top off the 

coolant if needed. If there is engine coolant in the engine oil or 
transmission fluid, the cause must be corrected and oil/fluid changed or 
major component damage may occur.

 

2003 Ford Pickup F150 

2003 ENGINE Engine Cooling - F150 Pickup

  

4. Inspect the coolant condition. 

1. Inspect the coolant color. 

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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.  

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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.  

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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-F6SE-19A511-AA only.  

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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.  

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An iridescent sheen on top of the coolant can indicate a trace of oil is entering the system. 
For additional information on engine diagnosis, refer to ENGINE SYSTEM - GENERAL 
INFORMATION .  

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A milky Brown color may indicate that either engine oil or transmission fluid is entering the 
cooling system. If transmission fluid is suspected, the cause may be a leaky radiator. Pressure 
test the cooling system. For additional information, refer to COMPONENT TESTS . If 
engine oil is suspected the cause of the leak may be internal to the engine. For additional 
information, refer to ENGINE SYSTEM - GENERAL INFORMATION .  

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If transmission fluid is contaminated with engine coolant, the cause may be a leaky radiator. 
Pressure test the system. For additional information, refer to the COMPONENT TESTS .  

2. If the engine coolant appearance is acceptable, test the engine coolant freezing point range with the 

battery and anti-freeze tester. 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. 

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Maximum coolant concentration is 60/40.  

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Minimum coolant concentration 40/60.  

3. Adjust coolant range and level if necessary: 

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If coolant is low, add specified coolant mixture only. 

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.

 

2003 Ford Pickup F150 

2003 ENGINE Engine Cooling - F150 Pickup

  

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If the engine coolant tests weak, add straight engine coolant until the readings are within 
acceptable levels.  

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If the engine coolant tests strong, remove some of the engine coolant and add water until the 
readings are within acceptable levels.  

4. Verify the coolant system is correctly filled and bled. For additional informational, refer to 

COOLING SYSTEM DRAINING, FILLING & BLEEDING .  

5. If equipped with visctronic drive fan, refer to SELF-DIAGNOSTICS - CNG, FLEX-FUEL & 

GASOLINE instruction for diagnosis of the visctronic drive fan system.  

6. If the concern remains after the inspection, determine the symptom(s). GO to SYMPTOM 

CHART .  

SYMPTOM CHART 

Fig. 7: Engine Cooling System Symptom Chart 
Courtesy of FORD MOTOR CO. 

PINPOINT TESTS 

Pinpoint Test A: Loss Of Coolant 

 

2003 Ford Pickup F150 

2003 ENGINE Engine Cooling - F150 Pickup

  

Fig. 8: Pinpoint Test A: Loss Of Coolant - Test Chart (Steps A1 - A2) 
Courtesy of FORD MOTOR CO. 

 

2003 Ford Pickup F150 

2003 ENGINE Engine Cooling - F150 Pickup