This could be related to upper intake manifold composite material that may degrade around the EGR stove pipe and could result in an internal or external coolant leak.
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.
IF degradation of upper intake manifold composite material is found, REPLACE the upper AND lower intake manifolds as per GM bulletin#01-06-01-007B. Most vehicles only require replacement of the upper intake manifold AND gasket but check closely.
Good luck,
Nov 18, 2009 at 2:32 AM
