When testing for cooling system leaks, especially those into the EGR or exhaust system, the EGR cooler can be pressure-tested in the vehicle to identify a leak or source of coolant loss. Testing in-vehicle is preferred due to the labor-intensive process required to remove the cooler and its related components.
GM-48974-30 features a pressure adapter to replace one existing hose and a plug to replace another hose, along with the necessary clamps. The pressure adapter is connected to the currently Essential GM-46091-1 Pressure Gauge Assembly. Once GM-46091-1 is connected to shop compressed air, its regulator is adjusted to allow a maximum of 10 psi into the EGR cooler. GM-46091-1 can shut off the supply of air, and the gauge is checked to determine if pressure is being lost through the EGR cooler.