My blazer always shoots out white smoke at startup but I know thats just oil seaping through the valve seals. Yesterday I tried pulling my boat and it started to constantly shoot out small amounts of white smoke. However, when I took the boat off and ran it for a while the smoke stopped. I also have a small oil leak and when I checked it, it needed about a quart. Is the white smoke from lack of oil or did I blow a head gasket?