The intake manifold gasket may develop and external engine oil or coolant leak. In some cases, an internal coolant leak may occur causing coolant to mix with the engine oil. Running the engine with a coolant/oil mix may result in engine damage. Replacing the intake manifold gasket should correct this issue.Google+
Car Problem Reports
Chevrolet Impala SS Intake Manifold Gaskets May Leak Coolant or Engine Oil
Chevrolet Impala SS Problem
Engines Affected: 5.3L V8, 5.7L V8
Visitor, 2006 Chevrolet Impala SS, 5.3L V8, 152,000 mi
Leaking dex-cool when the car is warm and it feels oily to the touch. Upper engine shows signs of leak. Love this car and I hope the intake gasket is the problem.