Leaking oil from the spark plug - 2001 Volvo S40

If the spark plug is oil fouled, you either have leaking valve seals, or bad piston rings. Bad rings would be accompanied by excessive blow-by. With the engine running, remove your oil filler cap. If there is air pulsing out of the filler tube, it your rings. If not, it is your valve seals.

Oil leaking into the spark plug wells is an indictor of a fairly serious problem that should be inspected and repaired immediately. It is almost always due to a failing gasket or O-ring but can also be the result of a failing piston or worn valve guides. Oil is leaking into spark plug well Inspection Service Cost YourMechanic

ring no seating or valve guides leaking past valve stem

Pull out the spark plugs and check for oil on the spark plugs. If you do have oil on the spark plugs, the valve seals are leaking. The top of the engine has to be taken apart to repair it. If this is not the problem, then the oil rings on the pistons are worn out and leaking oil into the combustion chamber. This is a very expensive repair.

If the oil is on the outside of the spark plugs, you could have leaking valve cover seals or gaskets.

Oil is unlikely to be leaking out of a spark plug, more likely leaking on to it. Many things can cause this including a damaged head or leaking cover gasket. If oil is truely leaking out of the spark plug then your engine is either very worn or your valve oil seals are shot

your need a valve cover gasket set. It comes with 4 rubber seals for the spark plug tower so oil does not leak on the plugs. Common problem, Simple to fix. Takes about an hour

Hi bravo956
i also have the same problem regarding the oil leak. this is due to the spark plug gasket leaking and you will need to replace them. they are circular gaskets about 1.5 inches across that fit to the underside of the rocker covers and prevent oil from seeping down the long spark plug hole. when i investigated my leak i assumed it was just the rocker cover gasket that was leaking but once everything was removed it is obvious.

hi you will find that the rocker cover is proberbly leaking into the the plugs housing replace the rocker cover gasket yates210456

You probably have a leaking valve cover gasket causing the leaking oil to collect in the spark plug tubes.
The miss fire is probably caused by the HT in the plug lead shorting through the oil and causing a weak spark.
Clean all the oil out and track down the leak.