GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1999 🢒 Eldorado 🢒 Engine 🢒 Engine Controls - 4.0L and 4.6L 🢒 Exhaust Gas Recirculation (EGR) System Cleaning

Caution: Avoid breathing fumes and swallowing EGR exhaust deposits when removing components for cleaning as bodily injury may result.

Whenever the EGR valve is removed the EGR system should be inspected and cleaned if needed. This will insure that the EGR system will function properly under all operating conditions. Proper EGR system service consists of the following five 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.
  3. EGR Valve Cleaning. If the EGR system is operating correctly, the EGR valve can be removed, checked for deposits, cleaned, and re-installed. Use the procedure below for this operation.
    4. 3.1. Remove the EGR valve from the engine. Refer to Exhaust Gas Recirculation Valve Replacement .
    3.2. 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.
    3.3.  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.
    3.4. 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 deposits are such that pintle/base interface can't 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, wire brush/wheel or sand blasting. Cleaning by these methods is not recommended.
    3.5.  Inspect the passage in the Crossover Water Pump Housing for deposits. Remove all loose particles.
    3.6. Replace EGR valve on engine, using a new gasket. Refer to Exhaust Gas Recirculation Valve Replacement .

    Object Number: 11797 Size: SH
  4. EGR passages in crossover water pump housing.
    5. 4.1. Remove crossover water pump Housing.
    4.2.  Remove 2 plugs (2) and clean passages with a wire brush. Remove all loose particles.
    4.3. Re-install crossover water pump housing.
  5. Wash-up with soap and water after any contact with deposits from the EGR System.