Mercury Mountaineer engine oil leak from intake manifold area on Mercury Mountaineer

Some Mercury Mountaineer owners report experiencing engine oil leaks from the intake manifold area, characterized by visible engine oil around the base of the manifold. This issue can lead to poor acceleration and decreased fuel economy due to increased friction from inadequate lubrication. The leaks are often attributed to failed manifold gaskets or seals, particularly if the intake manifold is positioned over an oil-lubricated section of the engine block. Owners may find that cleaning or replacing the PCV valve can help resolve the leak, although the specific repair method and costs can vary based on the leak's root cause. Additionally, those noticing clean oil on the dipstick alongside dirty oil seeping from the intake manifold exhaust crossover under load should take this as a sign to inspect and clean the PCV valve to prevent further complications.