My A 4 fired up this Spring May 1 .I ran out all the antifreeze.I live in Maine. It got in the mid 20's at night for the last 3 weeks. When I tried to start it again , no go. I found a 4 in crack in the exhaust manifold port side right under the firing order 1243. Water flooded the carb .A freeze plug blew off on the head bythe last most spark plug. I tore off the manifold and then today Ichecked the compression uh o uh o ,30 lbs in each cylinder have I destroyed my engine?