i have a 1995 chevy blazer with the 4.3 v-6 in it with CPI injection and when i removed the lower intake manifold i saw the coolant passage at front of it open all the way looked to the rear of manifold and there is what appears to be a rear coolant passge but both ports are plugged solid with some type of debris . has anyone else encountered this and if so can it be cleaned out or is it time for a new lower manifold. thanks in advance for any input

 

Take a look at the LIM itself. There is no rear cross-over tube in the manifold, just indentations. Clean things up as best you can. The problem wouldn't happen so much if the gasket wasn't blocked off over that port.

 

I had the same stuff when I did mine last year...sort of a wet "corky" substance. I thought the gook might have collected from when I mixed Dexcool with the regular green stuff. I thought it was like when a cake recipe says use only Gold Medal flour. Swartikk is correct (isn't he always) in that they are passages to nowhere but that stuff could break loose some day and clog up the radiator or heater core. I started wondering if there was similar stuff in the passages where I couldn't see it so I cleaned it out and flushed it with an air hose.

 

thanks for the information guys you just saved me a major headache . in locating a new manifold. i think they should have made a complete gasket in stead of having the hole there as if there was a port. thanks again