Skip the auto shop - Our mechanics make house calls

Q: Oil fouls one spark plug - possible cause and recommendations to repair.

asked by on

Must replace spark plug (only #4 cylinder) every 600-700 miles engine starts to idle rough due to dirty plug (carbon build up) believe to be from oil leak from damaged valve seal - any recommendatio how to go about repair

My car has 105000 miles.
My car has an automatic transmission.

Hi there. If oil is causing the spark plug on cylinder number 4 to foul out every 600 to 700 miles, then the valve guide seals to that cylinder are damaged and need replaced. The valve guide seals prevent excessive oil from entering the combustion chamber. Most of the time the intake valve guide seal is worn for the oil gets sucked down into the cylinder rather than pushed out. This causes the oil to mist into the cylinder coating the spark plug making it foul out. If you need further assistance with your spark plug fouling out due to excessive oil in the cylinder, then seek out a professional, such as one from Your Mechanic, to help you.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  • Home
  • Questions
  • Oil fouls one spark plug - possible cause and recommendations to repair.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Brake Warning Lamp still on

Typically a warning light needs to be cleared by a digital scanner completed by a professional mechanic if a repair has been made. Based on what you said our mechanic completed; there were no repairs. The brake light issue could...

Q: Advice on which type of gas to use on a 2009 Charger

It's probably okay if the car runs perfectly fine and you are not having any problems. The way you can really tell it is to pull off the spark plug and look at it. In a normal spark plug, there...

Q: Would the car tell the percentage of the life of the oil, my car includes oil changes but the dealer won't do it until the indicator shows the change oil soon message.

Hi there. There should be a select button with two directional arrows on the button. Push and hold the right directional arrow on the button and the dash should go from the odometer to the menu. Then scroll up by...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...