Hi my buddy has a 96 blazer 4.3L and after he drives it for awhile it starts making this whistling noise and starts spitting antifreeze out rite behind the alternator down by the intake manifold and where the head meet, im not sure but i told him it was probably the intake manifold gasket but im not sure, any suggestions??

 

head gasket could of pushed out or intake a blue laser light is the best way to see antifreeze leaks