I've been loosing coolant and recently it has gotten worse. I was a bit dumfounded as I could not see where the coolant was leaking from any of the hose connections, radiator, my oil was clean and my exhaust appeared to be clean. I did notice some staining under the water pump and so I replaced it on Monday evening. While doing so, I replaced my water pump mounting bolts. The coolant leak was still there. Yesterday evening, I found the source of my leak, several cracks on the engine block.
The telltale stains have been there since shortly after I installed the engine. I had wondered from time to time where they were coming from, now I don't have to wonder any more.