Oil Leak In Spark Plug Well – Know The Signs – What Can Happen

Oil Leaking Into Spark Plug Well
Oil Leaking Into Spark Plug Well

Having a oil leak in spark plug well can produce a variety of problems.

Oil making its way into the spark plug wells will drastically affect the engines performance.

As a result, Leading to misfires, increased oil consumption and excessive smoke.

Also, A oil leak in spark plug well can even lead to an engine fire.

Oil on a spark plug, or on spark plug wires, can cause unexpected problems. Issues like incorrect spark plug gap, leaking valve covers or moisture intrusion can also damage ignition coils. It can also foul the ignition coil, interfering with ignition timing. It’s import to fix this leak as soon as you discover it.

If the vehicle is exhibiting any of these symptoms, checking for a oil leak in spark plug well should be your first job.

Oil leaking Onto Spark Plug
Oil leaking Onto Spark Plug

Warning Signs:

  • Burning oil smell
  • Valve cover is dirty and leaking oil
  • Engine is low on oil
  • Engine is running rough and causing misfires
  • Overheating engine

Between the valve cover and the engine are gaskets that have the tendency to fail over time. Due to the high temperature of the engine the gaskets can get brittle, and start to leak.

The Two Most Common Places To Leak:

Leaking Valve Cover Gaskets

Between the valve cover and the engine are gaskets that tend to fail over time. Due to the high temperature of the engine the gaskets can get brittle, and start to leak. It is possible for the oil to leak into the spark plug wells. Leaking valve cover gaskets need to be repaired as quickly as possible, failing to do so can lead to further engine damage.

Failing O-Ring Seals

Spark Plug Tube Seals On Cylinder Head
Spark Plug Tube Seals On Cylinder Head

There are O-Ring seals at the bottom of the spark plug wells and if a seal starts to fail, oil can leak past these seals and into the spark plug well. Again, this issue should be repaired as soon as possible and the spark plugs should be replaced at the same time.


  • Classic cars are especially prone to oil leaking into the spark plug wells, so it’s important to know what to look for when assessing where a leak is coming from.
  • On late model cars it is almost always due to a failing gasket or O-ring around the spark plug tubes.

The best place to start is to look for any leaks. Determine what the leaking fluid actually is, oil, water, or coolant. It is very common to have oil leaks in this area of the engine.

Diagnosing Automotive Leaks Illustration Chart
Diagnosing Automotive Leaks Illustration Chart

Although the leak can sometimes be fixed by tightening the valve cover bolts, more often than not the valve cover gasket and seals will need to be replaced.

Conclusion

Sometimes when oil leaks from a valve cover gasket it leaks all the way down to the spark plug galley and eventually seeps inside the spark plug tubes. As a result, This will cause a misfire or reduce engine performance.

Finally, The vast majority of valve cover gaskets only require simple tools to replace. But the procedures vary from car to car.

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