Exhaust Gas Recirculation (EGR) System Cleaning

Whenever the exhaust gas recirculation (EGR) valve is removed the EGR system should be inspected and cleaned if necessary. This will ensure that the EGR system will function properly under all operating conditions. Proper EGR system service consists of the following 5 steps:

1. EGR system diagnosis-Diagnosis of the EGR system should be performed if PCM DTCs are set.
2. EGR valve pipe cleaning and checking for leaks-Clean and check the EGR pipe from the exhaust manifold to the EGR valve and the EGR pipe from the water pump crossover to the throttle body spacer. Refer to Exhaust Gas Recirculation (EGR) Pipe Replacement .
3. EGR valve cleaning-If the EGR system is operating correctly, the EGR valve can be removed, checked for deposits, cleaned, and reinstalled. Use the procedure below for this operation.
   1. Remove the EGR valve from the engine. Refer to Exhaust Gas Recirculation (EGR) Valve Replacement  .
   2. While holding the EGR valve in your hand, use a pencil eraser or other suitable soft instrument to depress the pintle several times. The pintle should move in and out smoothly. Replace any valve that exhibits tendencies to stick.
   3. While holding the EGR valve base in your hand, try to rotate the connector housing. Repeat for the coil housing. Replace any valve that exhibits looseness.
   4. Inspect the EGR valve pintle and seat for deposits. Use a cloth or other suitable soft device to remove deposits. Remove all loose particles. If the deposits are such that pintle/base interface cannot be cleaned adequately to allow the pintle to seal against the seat, replace the valve. Damage to the powdered metal EGR valve base will occur if cleaned with solvents, sharp tools, a wire brush or wheel, or by sand blasting. Cleaning by these methods is not recommended.
   5. Inspect the passage in the water crossover assembly for deposits. Remove all loose particles.
   6. Replace EGR valve on the engine using a new gasket. Refer to Exhaust Gas Recirculation (EGR) Valve Replacement  .
Fig 1: View Of Water Crossover Assembly
Courtesy of GENERAL MOTORS CORP.
4. Cleaning the EGR passages in the water crossover assembly.
   1. Remove the water crossover assembly. Refer to Coolant Crossover Pipe Replacement in Engine Cooling.
   2. Remove the 2 plugs (2) and clean the passages with a wire brush. Remove all loose particles.
   3. Install the water crossover assembly. Refer to Coolant Crossover Pipe Replacement in Engine Cooling.
5. Wash-up with soap and water after any contact with deposits from the EGR system.