I have a 4.3 lx/v6 that filled the cylinders with enough water to lock it up. I had the exhaust manifolds pressure tested and found no problems. Is it possiable for an intake manifold to cause this type of problem? engine ser# is of146501.
if it's not the manifolds, then you probably either have a cracked block or a blown head gasket. Do a search for "Water in Cylinders", and you'll get some good advice. Did you get all the water out and oil the cylinders?