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
GMC Savana 3500 Intake Manifold Gaskets May Leak Coolant or Engine Oil
GMC Savana 3500 Problem
Engines Affected: 5.7L V8, Gasoline
Average Mileage: 113,600 mi (53,000 mi - 157,000 mi)
Visitor, 2001 GMC Savana 3500, 5.7L V8, 130,000 mi
External coolant leak that diagnosed the problem. Using oil extensively for a couple of months leading up to this.
Visitor, 2001 GMC Savana 3500, 5.7L V8, 53,000 mi
changed oil and it was light brown with water mix, coolant has to be added regularly from leak.
replaced intake manifold gasket
Gasket leaking coolant externally, replace gasket