Wayne,
On the passenger side I had a piece of silicone that laid in the entire third cylinder eyebrow.
You can see the eyebrow crossover above. It was about three inches long of blue silicone and as I removed it there was some actually inside the hole about half inch. This is the same silicone I used on the pump. There was no other silicone used in or around the cooling system.
On the drivers side we found smaller pieces but in the eyebrow passages of two cylinders, 6 & 7. AFR tells me this is enough to cause overheating of the type I had.
I put that water pump on almost two years ago so I don't remember how much I put on only that it was probably too much. You know silicone will accumulate as you tighten down the bolts and the excess gets squeezed out. This can break loose at any time but usually not right away.
Do I have it all out? Who knows. I've blown out the heads a couple of times and will do it a few more times before installation.
Hopefully by the weekend I'll have it back on the road.
Roscoe