Engine Cooling System: Diagnosis Ford Focus I

Inspection and Verification

1. Verify the customer concern by operating the system.
2. Visually inspect for obvious signs of mechanical or electrical damage. Visual Inspection Chart VISUAL INSPECTION CHART Mechanical Electrical Leaks Coolant expansion tank cap and seal Coolant expansion tank Radiator Water pump Accessory drive belt Fuse(s) Wiring harness Loose or corroded connector(s) Cooling fan motor(s) Cylinder head temperature (CHT) sensor Powertrain control module (PCM)
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
4. If the cause is not visually evident, verify the symptom and refer to the «SYMPTOM CHART»(ref-204922-S03851062892005111500000) .

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1. Switch the engine off.
2. Open the hood and install protective fender covers. WARNING: Never remove the coolant expansion tank cap under any circumstances while the engine is operating. Failure to follow these instructions may result in damage to the cooling system or engine and may cause personal injury. To avoid having scalding hot water or steam blow out of the cooling system, use extreme care when removing the coolant expansion tank cap from a hot cooling system. Wait until the engine has cooled, then wrap a thick cloth around the coolant expansion tank cap and turn it slowly until the pressure begins to release, step back while the pressure is released from the cooling system. When certain all the pressure has been released (still with a cloth) turn and remove the coolant expansion tank cap. Failure to follow these instructions may result in personal injury.
3. Carefully remove the coolant expansion tank cap from the coolant expansion tank to release pressure in the cooling system. Add coolant to the coolant expansion tank as necessary.
4. Install the cooling system pressure tester to the coolant expansion tank and pressurize the cooling system to the coolant expansion tank cap lower limit.
5. Observe the gauge reading for approximately two minutes. Pressure should not drop during this time. If the system holds pressure, proceed to Step 8. If the pressure drops, check for leaks at the engine to heater core hoses, engine to radiator hoses, bypass hose, water valve hose (if applicable), thermostat housing gasket, radiator and heater core, etc. Also refer to engine system checks if a leak cannot be located in the cooling system. Correct any leaks found and recheck the system.
6. Release the cooling system pressure by turning the pressure relief screw on the cooling system pressure tester. Remove the cooling system pressure tester from the coolant expansion tank. Check the coolant level. Add coolant to the coolant expansion tank as necessary.
7. Carry out the «COOLANT EXPANSION TANK CAP PRESSURE TEST»(ref-204922-S28469493852005111500000) .

Radiator Leak Test, Removed From the Vehicle

Clean the radiator before leak testing to prevent contamination of the test tank. Leak test the radiator in clean water with 138 kPa (20 psi) air pressure.

A separate clean test tank is recommended for aluminum radiators. If a separate tank is not available for aluminum radiator testing, rinse the test tank each time before testing an aluminum radiator.

Check it thoroughly for air leaks. INSTALL a new radiator if necessary. REFER to appropriate RADIATOR under REMOVAL & INSTALLATION.

Coolant Expansion Tank Cap Pressure Test

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1. Carefully remove the coolant expansion tank cap from the coolant expansion tank to release pressure in the cooling system. Add coolant to the coolant expansion tank as necessary.
2. Use water to clean the area of the rubber seal and pressure relief valve. Install the cooling system pressure tester and adapter and immerse the coolant expansion tank pressure cap in water. NOTE: If the plunger of the pump is depressed too quickly, an erroneous pressure reading will result.
3. Slowly depress the plunger of the pressure test pump until the pressure gauge reading stops increasing, and note highest pressure reading obtained.
4. Release the cooling system pressure by turning the pressure release screw on the cooling system pressure tester. Tighten the pressure release screw and repeat step 3 at least twice to make sure the pressure test reading is repeatable and within acceptable gauge reading limits of the coolant expansion tank cap.
5. If the pressure test gauge readings are not within acceptable gauge reading limits, INSTALL a new coolant expansion tank cap.