GM-48974-5 EGR Cooler Pressure Tester Adapter (4HK1 - 5/8" hose) is used along with GM-46091-1 Pressure Regulator Assembly to test the EGR cooler for leaks between the coolant side and the exhaust side. The cooling system is drained, and the hoses are removed from the EGR cooler inlet and outlet. The pressure adapter from GM-48974-5 is attached to the EGR cooler on either the inlet or outlet, and the other end is plugged using the supplied cap. With the regulator completely open, GM-46091-1 is attached to shop air, and the regulator is gradually turned until 15 psi is reached. The valve on GM-46091-1 is closed, and the system is left. Pressure should be maintained for at least 15 minutes, with minimal pressure drop. Any significant pressure drop indicates the EGR cooler is leaking.
GM-48974-5 includes GM-48974-1 (5/8” adapter), GM-48974-2 5/8” (cap plug) and non-marring hose clamps to fit 5/8” hose connections. GM-48974-5 components are included in GM-48974.