what causes oil to leak on spark plugs ?
Most likely a blown head gasket, check the coolant and see if its muddy or oily looking and check the oil for bubbles and foaming. If you mean oil on the outside of the plugs, (not on the electrode) then it is most like a valve cover gasket leaking oil down onto the plugs.
Its probably the valve cover gasket(s), not the head gasket. Its a common problem.
Bad piston rings or head gasket.
broken oil rings.
valve cover gasket needs to be replaced with the spark plug oil seals also. should all be included in a fel-pro valve cover gasket set. assuming its the 4 cylinder car.
what a bunch of bull,none of this post makes sense,valve cover leaks on the outside when bad,only way to get oil on the plugs are bad valve seals or broken oil rings.
On a overhead cam engine the plug are recessed down in the block. This means there valve cover gasket seals the outside edge of the vale cover as well as the openings around the plugs. So the seal can fail around the plugs letting oil get into the plug area and it can eventually seep down the plugs. Be to check that you don't have a clogged pvc system causing a pressure build up. I've seen this cause similar leaks before.
valve cover gasket needs to be replaced with the spark plug oil seals also. should all be included in a fel-pro valve cover gasket set. assuming its the 4 cylinder car. http://www.wellbridal.com
That could be your piston rings.
Oil leaks into the spark plug when the bike is driven ob the road by pressiing the clucth.As a result the clutch get free, due to gap between the plates and oil packing in the clutch plate starts flowing to the engine in large amount under high pressure effect. This accumulates over the piston and produces unburned fuel. This fuel gets accumated on the top head as the piston moves from BDC to TDC. This fuel blocks and produces hinderance in starting of engine.
I have w reg fiesta had the head gasket done about a month ago. And now it's starting stuttering really bad and rev up and down and now wot start at all now and I have oil all over 2 spark plugs