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.

A: Hi there. If oil is causing the spark plug...

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

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: Ford Explorer shaking at idle

The main thing on those things when they do this, you should try the obvious. A lot of them get an intake manifold vacuum leaks. It's a very common problem on those vehicles. Of course, always check the motor mounts,...

Q: oil pressure light comes on when l stop at a light or when it idles then l push the gas peddle and it goes off.

When the oil pressure light comes on, the engine oil is loosing oil pressure. I recommend performing an oil change and filter change with a good brand filter. If the light is still coming on, then hook up a mechanical...

Q: I was driving and all of a sudden my car made a loud horrible screeching sound and it continues as long as the engine is running

The noise sounds like you have a belt pulley that is seized. You will need to either start the vehicle and look for the pulley to component that is not turning or will need to remove the serpentine belt and...

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 Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...