Oil on spark plugs, also called oil fouling, is commonly caused by failing valve stem guides and bad stem seals. As pressure builds up in the crankcase, excessive oil enters the combustion chamber through worn-out piston rings or cylinder walls and forces its way to spark plugs. Oil fouling can also be caused by transmission fluid sucked through malfunctioning vacuum modulators or leaking lubricants from engine turbochargers.Continue Reading
The most common sign of spark plug fouling is engine misfires, explains How Stuff Works. Oil blocks the electrical current needed to create sparks that combust fuel, leading to poor performance, higher fuel consumption and bad emissions. Misfiring engines shake badly during idling and can be felt throughout the vehicle. The excessive vibrations can cause engine mounting eventually to fail.
Extreme cases of oil fouling can cause hard starting, engine stalling and ignition coil failure. The ignition coil is connected to spark plugs by high-tension wires and sends surges of electricity to fire the plugs. Oil-fouled plugs send the surges back to the ignition coil instead of its normal path. These surge backups can push ignitions to failure.
According to AAA1Car.com, oil-fouled spark plugs are easily fixed by sanding the deposits and wiping them with a clean cloth, though replacing them is a better option.Learn more about Car Parts & Maintenance
Parts and tools needed for a car's tune-up include spark plugs, a fuel filter, a socket wrench, a spark plug socket, a spark plug gapping tool, the service manual, screwdrivers, crescent wrenches, a distributor cap, spark plug wires, an air filter, an oil filter, engine oil, a PCV valve, various engine fluids and replacement drive belts. Depending on the brands, tune-up parts cost between $50 and $100, not including tools.Full Answer >
The top reason ignition coils fail is bad spark plugs or plug wires. Another potential cause is heat and vibration, which can damage the ignition coil's windings and insulation. If an engine is experiencing repeated coil failures, the underlying cause may be resistance from worn spark plugs or excessive spark plug gap. In rare cases, the failure may be due to a lean fuel condition caused by leaky valves.Full Answer >
The ignition temperature of a given substance is the measure of the minimum temperature at which the substance ignites, without the presence of an external spark or flame. Because of the fact that the material auto-ignites at this temperature range, it is also referred to as the substance's auto-ignition temperature.Full Answer >
Replace the spark plugs in a Mercedes-Benz C200 by removing the two-piece engine cover, removing the coil packs via the 12 Torx bolts and replacing the six spark plugs. Reassemble the parts by reversing the order in which they were removed.Full Answer >