New Tool Availability - EN-48974 - EGR Cooler Pressure Tester Adapter Set to Diagnose Duramax Diesel Engine EGR Cooler Leaks into Combustion Chamber

An EGR Cooler Pressure Tester Adapter Set, EN-48974, was shipped essential to dealers in December 2007 to diagnose EGR cooler leaks on all Duramax engines equipped with an EGR system. This adapter set is designed to be used with J-46091-1 - Charge Air Cooler Tester Regulator to pressurize the EGR cooler with shop air and monitor for leakage.

Important:  Leaks from the EGR cooler may allow coolant to pass through the exhaust system and enter the combustion chambers on the right bank cylinders. Failure to inspect the EGR cooler for leaks may lead to a misdiagnosis for coolant in the combustion chamber.

EN-48974 -- EGR Cooler Pressure Tester Adapter Set

1. 544259 (2 Qty) 19 mm (3/4 Inch) Hose Clamps
2. EN-48974-3 (Qty 1) 19 mm (3/4 Inch) EGR Cooler Hose Adapter
3. EN-48974-4 (Qty 1) 19 mm (3/4 Inch) Cap Plug
4. 544258 (2 Qty) 15.9 mm (5/8 Inch) Hose Clamps
5. EN-48974-1 (Qty 1) 15.9 mm (5/8 Inch) EGR Cooler Hose Adapter
6. EN-48974-2 (Qty 1) 15.9 mm (5/8 Inch) Cap Plug

If an investigation of loss of coolant leads to coolant found in one or multiple cylinders on the right bank, test the EGR cooler for leakage before attempting any repairs. The cylinders affected will depend on which exhaust valves are open at the time of engine shutdown.

1. Partially drain the engine coolant to allow EGR cooler hose removal.
2. Install the end cap and clamp of EN-48974 - EGR Cooler Pressure Tester Adapter Set to one of the EGR cooler hose barbs and install the pressure tester adapter hose and clamp to the other EGR cooler hose barb.

Important: SOME J-46091-1 REGULATORS MAY BE PRESET AT 30 PSI WITH THE ADJUSTING KNOB RIVETED IN PLACE. THE RIVET HEAD MUST BE DRILLED OUT WITH A 5/16" DRILL BIT BEFORE ADJUSTMENT. DO NOT DRILL MORE THAN 1/8" IN DEPTH, OR JUST ENOUGH TO REMOVE THE RIVET HEAD. THE RIVET SHAFT DOES NOT HAVE TO BE REMOVED FROM THE REGULATOR.

3. Back off the regulator on J-46091-1 - Charge Air Cooler Tester Regulator by turning counterclockwise until it stops.
4. Connect J-46091-1 - Charge Air Cooler Tester Regulator to EN-48974 - EGR Cooler Pressure Tester Adapter Set, and connect shop air to J-46091-1.
5. Open the shutoff valve, then slowly turn the regulator on J-46091-1 clockwise until the gauge reads 15 psi.
6. Shut off the valve on J-46091-1 and monitor the gauge for leak down. Replace the EGR cooler if it does not hold pressure.