I have a 1986 jetcraft with a 302 1991 Kem marine motor, ran good all day. The temp got to 210 while idling at the boat launch to load up, I noticed it so i back up and got water moving that dropped the temp alot back to 160, when we loaded the boat i went to clear the sand trap and pull the plug. There was a crap ton of anti freeze in the bottom of the boat, and very little in the over flow and in the heat exchanger, i checked the exchanger today and there were a few clogged holes but not more than 10. What else should i look for. how can this much antifreeze escape through the cap?