If you find oil on a spark plug, on the spark plug threads, or in the spark plug well, oil is leaking from the spark plug well gaskets. Oil collected in the spark plug well, also known as the spark plug tube, is a problem since it can pile up on the ignition coil and spark plug until it causes runability issues and possibly a check engine light. This post covers the signs of a spark plug tube gasket leak, why oil would cover a spark plug or ignition coil, and how you can fix it.
How to Fix Oil in the Spark Plug Well
Symptoms of a Spark Plug Well Gasket Leak
- Engine performance issues like high oil consumption or misfires
- Check engine light
- Oil collected in the spark plug tube, on the spark plugs, or on the ignition coils
If the spark plug tube’s o-ring is leaking oil, it can cause problems with engine performance like misfires or consistently low oil levels from excessive oil consumption. A check engine light could also appear on the dash. You may also notice oil on the spark plugs and ignition coils, or find it inside the spark plug tube.
Causes of Oil on the Spark Plugs
Oil lubricates the camshafts and lifters, and these moving parts sputter the oil up against the valve cover so it can fall back to the oil pan. The valve cover has gaskets to prevent oil from collecting inside the spark plug well. If the spark plug tube gaskets are worn, stiff, or damaged, there will be a weak seal, and oil will collect inside of the spark plug tube.
How to Fix a Spark Plug Well Gasket Leak
Steps for How to Fix a Spark Plug Well Gasket Leak
- Remove the Valve Cover
The easiest way to replace the spark plug well’s o-rings is on a bench with the valve cover removed. Remove the valve cover to access the spark plug well gaskets
- Remove the Spark Plug Well Gasket
Place a flat blade screwdriver between the valve cover and the gasket and tap the screwdriver to wedge it. Then pry up the gasket with a flat blade screwdriver without damaging the metal.
- Install a New Spark Plug Well Gasket
Apply a thin amount of engine oil or grease to the outside of the gasket before installing. Line the gasket into place on the valve cover. Place a socket that covers the size of the gasket on top and press the gasket in by tapping the socket with a hammer. Once the gasket is fully pressed all the way in to the valve cover, repeat this process for the remaining o-rings.
- Replace the Valve Cover Gasket
Once all the o-rings are replaced, replace the valve cover gasket before reinstalling the valve cover
- Clean the Spark Plug Tube with Sandpaper
Before installing the valve cover, clean the spark plug tube of any dark build-up with sandpaper
- Replace the Valve Cover
Tighten the valve cover once the gaskets are replaced and the spark plug tube is clean
- Remove Oil from the Spark Plug Well
Depending on the amount you can vacuum the oil out, clean it out with a cloth rag, or clean it with a cloth rag and a blow gun.
To clean the spark plug tube with a cloth and blow gun, stuff the cloth and blow gun into the spark plug well so it can catch any oil trying to escape as the air is pumped in. Remove any oil that may have landed on the valve cover.
Learn How to Diagnose and Replace Parts Yourself
Find out how to diagnose and replace parts specific to many makes and models. 1A Auto’s how-to video library has thousands of videos with professional advice to help you diagnose and replace parts on your own car.
- Recycling Waste Fluids and Oils? How to Dispose of Motor Oil, Antifreeze, Brake Fluid, and More
- Why is My Car Leaking Oil?
- Excessive Oil Consumption: Why It Happens, How to Prevent It, and How to Fix It
- How to Diagnose an Engine Misfire
- Signs of a Failing or Bad Ignition Coil
- How to Test If an Ignition Coil Is Bad