I am considering buying a used boat (1990 Glastron Sierra 170) that I has the condition listed as the subject. I am interested in opinions on the most likely cause and extent of damage as I will be completing an inspection next week. <br />Other facts:<br />supposedly did not overheat<br />engine cranks fine<br />no oil in water or milky substance<br />am being told minor repair - possible cylinder head crack or gasket leak<br /><br />What should I be checking, and how, to determine the extent of the needed repairs?