Oil on your spark plugs without smoke usually means a gasket or seal (like the valve cover gasket or spark plug tube seals) is leaking oil into the spark plug well, not burning it in the cylinder; it collects around the plug base, not the electrode, so it won't necessarily smoke but will cause misfires and poor performance. Key culprits are old valve cover gaskets, worn spark plug tube seals, or sometimes cam seals, allowing oil to drip down into the plug recesses, a common issue that requires replacing these seals.
Oil on your spark plugs may be due to worn piston rings or damaged valve seals, or it could be from excessive crankcase pressure or a failing PCV valve.
I would have it replaced by a shop if you would have to drive that far. Oil leaking into the spark plug hole will ruin the ignition coil and it will foul up the spark plug causing a misfire.
You can dry it out or blow it off or spray it with some carb cleaner or brake cleaner which will speed up the process or just use a cigarette lighter and heat it up for 10 or 15 seconds on the center electrode near the tip where it jumps the gap.
Yes, a blown head gasket can cause both of those. The head gasket keeps the oil out of the upper cylinder, so if the gasket has failed oil will be able to seep into the upper cylinder and onto the spark plug.
The first signs of a blown head gasket often include engine overheating, thick white smoke from the exhaust (sweet smell), milky or frothy engine oil, and bubbles in the coolant reservoir, indicating coolant is leaking into the combustion chamber or oil passages, leading to power loss and rough running. A critical early sign is also unexplained coolant loss with no visible external leaks.
Diagnosing Head Gasket Leak Signs from Spark Plug Condition
If spark plugs don't appear steam cleaned, it doesn't rule out a head gasket leak. A blown head gasket can cause coolant to enter the combustion chamber, leaving deposits or steam-cleaned plugs. Inspect for symptoms like white smoke, overheating, or milky oil.
Engine misfiring can occur in any of the engine's cylinders due to incomplete fuel/air mixture combustion. With oil in the spark plug well, the plug is less likely to generate enough spark to complete the ignition of the gas/air mixture. As a result, you will begin to notice misfiring in your vehicle's engine.
After switching off, the unburned fuel remains in the engine. That wets the spark plugs, which prevents ignition and makes the car difficult to re-start. The petrol can also cause 'bore wash' when it removes the oil around the cylinder's piston rings.
WD-40 Multi-use Product is ideal for cleaning spark plugs.
Black, oily deposits on the electrodes and insulator tip points to an oil-fouled plug. Oil could be leaking into the cylinders, getting past pistons that are worn or valve guides that are worn. Finding the source of the leak is very important – consult a mechanic for guidance.
Spark plugs can get contaminated with oil for two reasons: a leaking component (e.g. a tube seal) in the well or an engine-related issue that's causing oil to enter the combustion chamber. Oiled spark plugs won't perform as they should. As a result, the engine can misfire.
Spark plugs aren't supposed to have ANY oil on them. Before you pulled them out, you should probably shine a light down around them to see if there's any debris. If you had, you'd have probably seen oil pooled around the tops of them.
Overheating: Overheating can cause the spark plug's electrodes to wear out more quickly. This is often due to issues like incorrect spark plug gap, poor fuel quality, too little fuel available for combustion, or engine overheating.
The most common misdiagnoses of a blown head gasket are disappearing coolant and an engine that seems to be overheating for no apparent reason. To determine the exact cause, try refilling your cooling system to see if this keeps your car cool. If it does so for several days, then you likely only have a coolant leak.
Compression Test
Conducting a compression test on each cylinder is a valuable diagnostic tool for identifying both a blown head gasket and a cracked block. Significant variation in compression levels between cylinders could indicate a blown head gasket, as the gasket's failure can affect the seal between cylinders.
Loss of Engine Power: The puffing or clicking sounds associated with a blown head gasket signify a loss of compression in one or more cylinders. This loss of compression leads to reduced engine power and poor acceleration. It can make your vehicle sluggish and unresponsive.
How Do I Fix a Blown Head Gasket at Home?