Ford Workshop Service and Repair Manuals

Thermostat

The 1.6L Duratec-16V Ti-VCT engine is equipped with an electronic thermostat. The electronic thermostat will manually open if the coolant temperature has reached 98°C and there is no current flowing to the thermostat electrical element. When the engine is under load the electrical thermostat will receive a current from the PCM. The electrical current will heat the element inside the thermostat to allow the engine coolant to flow through the radiator when the coolant temperature has reached 60°C.

Coolant degas shutoff valve

The coolant degas shutoff valve is designed to stop the degas process during cold start. Shortly after the engine is started, the coolant degas shutoff valve will close and reduce the coolant flowing through the engine which will improve cold start fuel economy and warm up time of the coolant. When the coolant temperature has reached 80°C the valve will open and allow hot coolant to circulate through the coolant expansion tank.

Engine Coolant

WARNING:Engine coolant contains monoethylene glycol and other constituents which are toxic if taken internally and can be absorbed into the skin after prolonged contact.

Engine coolant concentration should be checked through the neck of the expansion tank with a hydrometer. The acceptable range of specific gravity (sg) of correctly balanced fluids is between 1.06 and 1.07kg/l, which represents an engine coolant concentration between 40% and 55%. If the concentration falls below 40% there is insufficient low temperature protection and the corrosion resistance will be inadequate. In such cases the concentration must be brought back to specification.

The coolant used can be either blue-green colored Motorcraft Super Plus 4 or orange colored Motorcraft Super Plus 2000. Motorcraft Super Plus 2000 is a non silicated organic acid technology (OAT) coolant, and must not be mixed with other coolant types. For cooling system top up, only use coolant which meets the correct specification and is compatible with the existing coolant.
For additional information, refer to: Specifications (303-03B Engine Cooling - 1.6L Duratec-16V Ti-VCT (Sigma), Specifications).

Changing Coolant

WARNING:When releasing the system pressure, cover the expansion tank cap with a thick cloth to prevent the possibility of coolant scalding. Failure to follow this instruction may result in personal injury.

CAUTION:When draining the coolant or changing any cooling system components, it is imperative that no coolant comes into contact with the camshaft drive belt or accessory drive belt. If necessary the belt should be removed. Contamination of the belt may result in belt failure.

NOTE:Providing the coolant has not been contaminated with other fluids or foreign matter, the robust corrosion resistance properties of this coolant means that it can be re-used after changing an aluminium cooling system component, although the concentration should always be checked and maintained within specification.

This engine coolant should be changed after a period of 10 years or 150 000 miles, whichever occurs sooner. Refill the cooling system with coolant which meets the correct specification and is compatible with the existing coolant.
For additional information, refer to: Specifications (303-03B Engine Cooling - 1.6L Duratec-16V Ti-VCT (Sigma), Specifications).

Fail-Safe Cooling

The vehicle has a strategy built into the powertrain control module PCM that will control the engine if the engine starts to overheat.

If the engine starts to overheat, stage 1 of the strategy will commence. The ECT sensor transmits a signal to the PCM which then moves the temperature gauge pointer into the red zone.

If the engine is not switched off and the temperature continues to rise, the Powertrain Check lamp is illuminated. This indicates to the driver that the engine is approaching critical limits and should stop. At this point DTC p1285 is set in the PCM which can be retrieved using WDS.

If the lamp and temperature gauge are ignored by the driver, stage 2 of the strategy will commence. The PCM will start to control the engine by cutting out two cylinders and restricting the rpm to below 3000 rpm. Simultaneously the Malfunction Indicator Lamp (MIL) will be illuminated. This indicates that long term engine damage may occur and vehicle emissions will be affected. At this point DTC p1299 is set in the PCM which can be retrieved using WDS.

Air is drawn into the deactivated cylinders which helps to control the temperature of the engine internal components. The deactivated cylinders are alternated to allow even cooling of all the cylinders.

NOTE:If the driver is using a high percentage of throttle travel (for example, an overtaking maneuver) when the PCM starts engine deactivation (stage 2), the deactivation will be delayed for 10 seconds.

NOTE:After 2-cylinder operation has begun, the engine will not revert to 4-cylinder operation, even if the temperature should fall, until the ignition is switched off and then on again.

NOTE:The MIL can only be extinguished by using WDS after the fault has been rectified and the DTC cleared.

If the engine temperature still continues to rise, stage 3 of the strategy will commence. This will result in the engine being totally disabled before major engine damage or seizure occurs. The Powertrain Check lamp will begin to flash, indicating to the driver that the engine will be switched off after 30 seconds. This allows the driver time to choose a suitable parking place.