Download Engine Coolant Consumption or Coolant Leak (Inspect For Material Degradation/Replace Intake Manifolds) Models: 1995-1997 Buick Riviera 1995-1999 Buick LeSabre, Park Avenue 1996-1999 Buick Regal 1998-1999 Chevrolet Lumina, Monte Carlo 1995-1996 Oldsmobile Ninety-Eight 1995-1999 Oldsmobile Eighty-Eight 1998-1999 Oldsmobile Intrigue 1995-1999 Pontiac Bonneville 1997-1999 Pontiac Grand Prix with 3.8L Engine (VIN K — RPO L36) Condition Some customers may comment on excessive engine coolant consumption, or an engine coolant leak near or under the throttle body area of the upper intake manifold. Cause Upper intake manifold composite material may degrade around the EGR stove pipe and could result in an internal or external coolant leak. Correction 1. Follow the upper intake manifold removal instructions found in the Engine Unit Repair Section of the Service Information Manual. 2. Refer to the arrow in the illustration of the upper intake manifold above. Inspect the inner diameter of the EGR passage for signs of material degradation. Degradation will appear as “pitting” of the composite material in the EGR port passage. 3. If degradation of upper intake manifold composite material is found, replace the lower and upper intake manifolds with the following part numbers: 4. Follow the lower and upper intake manifold installation instructions found in the Engine Unit Repair Section of the appropriate Service Manual. 5. If degradation is not apparent, skip to Step 7. 6. Verify the repair. 7. If no degradation is found, evaluate the vehicle for other causes of excessive coolant consumption as noted in the Engine Diagnosis Section of the appropriate Service Manual. Parts Information Warranty Information For vehicles repaired under warranty, use: • Gasket Kit, Upper Intake Manifold — 89017554 • Manifold Kit, Upper Intake — 89017272 • Gasket, Lower Intake Manifold — 89017400 • Manifold, Lower Intake — 24508923
