The camshaft seal is a round oil seal located in the cylinder head. It is responsible for sealing the end of the engine’s camshaft or camshafts between the top of the cylinder head and the valve cover gasket. Camshaft seals are usually made of durable rubber materials that allow them to have a long service life. However, over time, these seals can wear out and begin to leak oil. Any sort of engine oil leak is bad for the engine, as the oil is what protects the metal internal components of the engine from friction. Usually, a bad or failing camshaft seal will produce a few symptoms that can notify the driver that a problem has occurred and needs to be serviced.
Visible signs of oil leakage
The most obvious symptom of a problem with the camshaft seal is visible signs of oil leakage. Camshaft seals are usually located on the top of the cylinder head towards the rear of the engine and near the firewall. When they begin to leak, there will usually be traces of oil on the rear of the engine right below the valve cover, which can sometimes flow to the edges or corners of the engine.
Smoke from the engine bay
Another common symptom of a bad camshaft seal is smoke coming from the engine bay. If the oil leaking from a camshaft seal finds its way to a hot exhaust manifold or pipe, it will burn up on contact and produce smoke or produce the odor of smoke. The amount of smoke and intensity of the odor will depend on the severity of the oil leak. Small leaks may produce faint streaks of smoke, while large leaks may produce obvious trails.
A defective camshaft seal may not have an immediate or direct effect on engine performance, however, it can have an effect on reliability - as any oil leak is a compromise to the engine’s lubrication. If your vehicle displays any of the symptoms above, or if you suspect that your camshaft seal may be leaking, have the vehicle inspected by a professional technician, such as one from YourMechanic, to determine if your car needs a camshaft seal replacement.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Camshaft Seal and was authored by Ed Ruelas.