If you are finding oil leaking from the driver side of your 5.9L Cummins engine block, it may be a faulty pushrod or tappet cover gasket. Due to the factory construction, the OEM rubber can deteriorate over time causing an oil leak. Replace this failed gasket with the Cometic Replacement Pushrod Cover Gasket. This gasket is designed to meet or exceed factory specifications and will create a leak free seal.