Just bought a 2000 Discovery. Seller said the local British repair shop diagnosed blown head gasket. I removed head and found signs of leakage on head gasket towards spark plug side of block on 6 and 8 cylinders. But what has me worried is number 6 cylinder liner is protruding above the block .009 inch. The pistons in each of these cylinder look the same as others and the valves all look the same so I do not see any signs of coolant getting into anything. I have read about dropped liners but I did not see anything about raised liners. What does this mean? The other seven liners are flush with the top of the block. The odometer shows 180,000 miles and the repair records shows a head gasket job about 80,000 miles ago.