The CTS-V Sport, XTS-V Sport and ATS-V intercooler is a sealed system with total capacity of 3.3 quarts. Any air pocket that reaches the intercooler pump will cause it to shut off after five seconds, rendering your intercooler worthless. This can create an unsafe scenario for a turbocharged car, especially when boost is turned up via an aftermarket tune. When the intercooler pump is off, manifold air temperature (MAT) skyrockets under boost. The ECM will respond by reducing target boost, pulling ignition timing advance and closing the throttle. The factory system doesn’t have any type of reservoir, which leaves no convenient way to fill and bleed the system. Cadillac dealerships are supposed to have special equipment do properly fill and bleed these intercoolers, but many don’t. And hardly any dealerships have the knowledge and experience required to work on these systems. This is why we created the Tapout intercooler fill/bleed kit, which is easily installed and provides everything needed to properly fill and bleed your CTS-V Sport, XTS-V Sport or ATS-V intercooler system.
The CTS-V Sport, XTS-V Sport and ATS-V intercooler is a sealed system with total capacity of 3.3 quarts. Any air pocket that reaches the intercooler pump will cause it to shut off after five seconds, rendering your intercooler worthless. This can create an unsafe scenario for a turbocharged car...
www.tapouttuning.com
The CT4-V Blackwing has a much improved intercooler system, even though overall system capacity has been reduced from 3.3 to 2.9 quarts. In summary, this system was designed for the CT5-V Blackwing and got dropped into the CT4-V Blackwing with way less power. Even with 26 pounds of boost and nearly 700 whp, our flagship CT4-V Blackwing’s factory intercooler has no problem keeping up.
The heat exchangers are new, with cores are almost twice as large as the ones on the ATS-V, and more efficient too, no longer having the hibachi grill on the side coolers that restricted flow. These are now manufactured in house by a GM subsidiary in the U.S.A. The air flow to the coolers themselves is so much more efficient, in that every radius in the grille mesh, surfaces has been dialed in to ensure air is hitting as much of the area of the heat exchangers as possible, including tilting the transmission cooler to expose the bottom 2” of the main radiator to fresh airflow. The intercooler pump design changed due to the new electrical architecture that provides much more control via the ECM, and again, it’s a pump designed or the big V8s and used on the small car. There is a Y in the pipes on top of the engine is actually called a mini reservoir and it has a screw on top to make bleeding that circuit way simpler. There is also a ‘tower’, which serves as a small reservoir to catch any air in the system and trap it which results in overall better efficiency of the system. Overall GM designed the pipes to be less distance, less fluid (mass) but also flow more efficiently and allow significantly better air bleeding/less trapping.
Speaking of cooling overall, the radiator shroud for the fan is unique to Blackwings, with two added doors/flaps that open to make it more efficient, and they also tuned the stiffening ribs of it to not restrict airflow but stay stiff enough to meet modals required. The main radiator is all different and is not sectioned like the ATS-V was. The new CT4-V Blackwing engine cooling system includes the main radiator and the left hand side auxiliary radiator for the charged air system. The new CT4-V Blackwing charged air intercooler system includes the main/center/front low temperature radiator and the right hand side auxiliary radiator. Then there is the core that lays horizontal, which is used for transmission and differential cooling.
Special thanks to
@Mirza Grebovic and his team for the excellent design work, and for helping our team to understand all the cooling system improvements.
, but every once and a while I find the rubber cap on this 'thing' popped off (it was hanging loose when i bought the car and its been bugging me since to know what it is). I put the cap back on whenever I see it off, but I have no idea what it does. 
