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. A considerable 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!

 

A LIM gasket leak could allow coolant into the cylinders.

Coolant intrusion into the cylinder will actually result in the plugs being steam cleaned.

You can run a compression test to see if you have signs of a head gasket problem. You can also pressurize the cooling system up to 16psi and look/listen for leaks.