Its a 87 four winns 19ft mercruiser with 4.3..I ran it for 3-4 days on vacation and the oil level came up,i know;cracked block..BUT,is there any other possibilities besides head gasket?? It doesnt run hot,runs great and 1st oil change when i got it oil had no milk to it(changed through dipstick)..The engine also has new exhaust manifolds,could that add water(cracked manifold) and thats why theyve been changed?? Engine has 380hrs,and runs very good..Maybe bad fuel pump seal??Any suggestions,tests i could do??THANKS in advance!