OTC 5039 Charged Air Cooler Tester for Class 7 and Class 8 Trucks
This is the easy way to find air leaks in the charged air cooler  systems used on class 7 and 8 truck engines. The tester features  a large 2-1/2" 0-60 PSI pressure gauge regulator and relief valve and two safety cables. It also has quick disconnect air fittings that attach to a 3" 3-1/2" or 4" cooler hose.