1949 Chevy ton and a half.

I had a slight head gasket leak of engine coolant. I put in a bottle of that liquid stuff with the gooey plus the metal flakes. It stopped the head gasket leak but then I started having an overheating problem. I took the radiator out and it was full of globular slime. I finally got all that flushed out. The thermostat was also goobered up with slime. Checked the water pump and it looks fine (see below). Still had the overheating problem.

So I tore it all down again, made sure water would run through the radiator as fast as I poured it in. It does. Put it all back together.... still overheats. Tore it down again. This time I ran a roto-rooter toilet snake through the water jacket of the engine block. Got caught on that stupid oil line that goes through the water jacket. (What a dumb thing the engineers did.) Got out the air compressor and blew air in one hole of the block waterjacket and it comes out the other hole. I haven't put it back together again yet because I only have one more water pump gasket.

This is what I believe: either a) there must be (have been) a gooey blockage inside the engine block water jacket or b) the water pump suddenly stopped working just at the time I put in the gooey head gasket sealer stuff.

My question is this. The water pump impeller turns when I turn the pulley. The impeller looks to be cast iron and has all the vanes intact. It seems darned unlikely that the water pump on that thing can fail! Has anyone seen a water pump of this type fail?

Harrell