Hi, I have a ’95 Blazer with a 4.3L Vortec V6. The engine has developed an internal coolant leak. No external leaks are visible. Aconsiderable amount of white smoke comes out of the exhaust. The coolant level drops and there appears to be coolant dripping out where the right exhaust manifold mates to the Y-pipe. I pulled the right side plugs. The #6 plug appeared to have a little more buildup on it but all appeared dry. I cranked the engine over, but nothing came out of the plugholes. The question I have is, could this leak be from the lower intake manifold gasket or a head gasket problem or worse? Thanks!