Dealing with this with daughters 05 X3 2.5 , had oil leak under car. Shop changed valve cover gasket and seals for the coil tube . This is not that easy to do right , because the car ran with bad miss after 30 km . Had a bad altercation with and plan on seeing them in small claims court .
I removed the plugs , the back 4 were dripping oil. New plugs , gaped 42mm , installed. Start car , runs like a 6 cylinder BMW .
one week later we pull the plugs after 50 km of driving and we found oil on the last 4 plugs. [br]
ordered Felpro gasket kit, and after testing found 4 coils mis matched and sporadicly failing. Ordered 6 Bosch Coils from eBay . Installed new gaskets And seals with great care , new coils and the new plugs . Car runs perfect now .