Reflux can damage one kidney more than the other. If one kidney is badly scarred it might need removing for two possible reasons. Firstly a damaged kidney can cause high blood pressure. This will need life long treatment with drugs to prevent the blood pressure damaging his blood vessels and other organs (including his good kidney).
The average cost for a rear main seal replacement is between $659 to $860. Labor costs are estimated between $631 to $797 while parts are priced between $28 to $63.
Running the engine low on oil can cause the rear main seal to become dry, and a crack or tear in the rubber can occur. This should be another good reason to change your engine oil regularly and use a good quality oil.