Hello Mr Black, for you to be able to feel a gasket or O ring with your fingers tips should be impossible given that all bolts attatched have been toqued to manufacturers specs. but you haven't mentioned what vehicle are we talking about. One of many possible reasons for your problem could be a blown head gasket, but their should be a few tell tale signs if this is the case. Engine overheating, poor compression lack of of pulling power, water in the oil filler cap, oil in the exspansion bottle. if any of these symptoms are there then you will have to remove the cylinder head to examine it futher. but before you go to the exspense of a head removal i suggest you give it a compression test, if you get more than 10 lbs variation between adjacient cylinders then your cylinder head is warped and will have to be removed and refaced plus you still have to find the reason for the being warped.
derek
February 2009