On a side note have you checked your PCV valve .[FONT=Arial, Helvetica, sans-serif]When a PCV valve stops working, pressure builds up inside the valve cover. This pressure can cause a number of problems for the engine, including an oil leak, particularly at the valve pan gasket. Clogged PCV valves may make an engine run poorly, decrease gas mileage and increase vehicle emissions , if it is stopped up may have caused the leak in the first place an they over compensated by tightening the valve cover to much an cracking it , just something to check .[/FONT]