Here's the instructions from Ford on flushing the CAC.
I'd avoid dish soaps like Cascade, some of these are pretty harsh on aluminum.
Flushing
1. NOTICE:
Do not use a high-pressure power washer to clean the Charge Air Cooler (CAC) or damage to the CAC may occur.
NOTE:
Drain all contaminates such as coolant, fuel and oil prior to cleaning the CAC.
NOTE:
Thoroughly clean the joint clamp areas as well as the turbocharger connection, engine connection and the CAC connections, using metal brake parts
cleaner.
Lay the CAC flat with the inlet and outlet ports pointing up.
2. NOTE:
Plug or cap the CAC openings prior to agitating.
Add an appropriate amount of a commercially available detergent cleaner such as Simple Green® Pro HD, or equivalent, to the CAC. Follow the
manufacturer's directions for heavy cleaning. Fill the CAC to 40% of its volume with water.
3. Raise one end of the CAC and agitate it by hand for at least 5 minutes.
4. Raise the other end of the CAC and agitate it in the other direction by hand for at least 5 minutes.
5. Drain the CAC.
6. Flush the CAC thoroughly with clean water.
7. Repeat Steps 1 through 6 until no contaminates are found in the flushing water.
8. Allow the CAC to air dry.
9. NOTE:
A leak test must be performed prior to painting or installing the CAC.
Perform the Leak Test — Charge Air Cooler (CAC).
