A friend has a coolant leak on his Blazer. Not the best picture ever, but where it's circled... there is coolant bubbling right there (when it's running). It appears to be just below the valve cover coming from the intake manifold? He's really hoping it's not a head gasket. Could it be possible that a head gasket leak could manifest right there? Also, the oil is good and clean. No sign of coolant contamination. Thanks!