Normal Operation

WARNING: This page is about a different car, the 2012 Ford Pickup, 2012 Ford F550 Super Duty, 2012 Ford F450 Super Duty, and 2012 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

The secondary cooling system maintains temperatures in the Charge Air Cooler (CAC), the fuel cooler, the transmission cooler and the EGR cooler during operation. Correct coolant flow through the radiator and the remaining components of the system is essential to maintaining correct temperatures.

Coolant flows primarily from the coolant pump to the radiator circuit and then to the transmission fluid cooler and EGR cooler from the high temperature thermostat and the CAC and the fuel cooler from the low temperature thermostat. The coolant flows from each component to the degas bottle and then back to the coolant pump. The coolant pump is operated by engine rotation through a pulley which is driven by the accessory drive belt to circulate the coolant. The coolant thermostats are control valves actuated by coolant temperature. When the thermostats are closed, coolant flow bypasses the radiator circuit and flows to the 4 cooling components. When the thermostats are opened, coolant is allowed to flow through the radiator circuit in order to transfer component-generated heat to the outside air.

System overheating generally occurs when there is a disruption in the ability to control either coolant flow at the proper rate, the inability to transfer heat from the cooling components through the coolant (including low coolant) or an inability to transfer component-generated heat to the outside air through the radiator.

DTC P007D (CACT Sensor Circuit High) - Indicates a higher than expected air temperature as the air flows out of the CAC.
DTC P2185 (Engine Coolant Temperature (ECT) Sensor 2 Circuit High) - Indicates higher than expected coolant temperature as the coolant flows into the EGR cooler.

This pinpoint test is intended to diagnose the following:

Low coolant level
External engine coolant leak
Airlock in system
Pressure relief cap installation
Restricted airflow through the A/C condenser or radiator
Internal coolant leak
Coolant condition/concentration
Accessory drive components
Non-OEM engine enhancement components
Thermostats
ECT sensor - secondary cooling system ECT 2
Charge Air Cooler Temperature (CACT) sensor
Coolant pump
Coolant flow restriction