Be sure you use a torque wrench to torque the cap, this will prevent potential damage to the plastic cap. The torque has nothing to do with sealing on the cartridge style oil filters, it is to keep the cap from backing off. If you torque it correctly, and it leaks, do not tighten it more, remove it and make sure the “O” rings are still in the correct grooves, and the cap is not damaged or cracked. Also when installing the “O” Rings use clean new oil, old used oil may have contaminates that can cause a leak.