Oh boy, at least around these parts, mice, mud wasps and of course, water! No easy way to tell. Drain the oil, see what comes out. As mentioned, mice can ruin radiators, carbs, engines, and upholstery (don't ask how I know THAT one!) Best of luck!
1940 Chevy 1/2 ton pickup "KC" A day without sunshine is like, well, ..... dark!
