I just pulled one of the engine spark plugs and found oil on it but the oil is not on the spark plug tip at all the til is dry. the oil was not much not like dripping oil but there was oil I'm really disappointed and dippresed I know it's not simple issue but not sure if it's head gasket I hope it's valve cover gasket or valve seals .

where to start ? how to idintefy the faliure part ?

 

Do you have a XJ8 or XK8? If yes, I'm a little unclear as to what you're saying. Do you mean you have oil on the body of the plug above the threads? If so you need to replace the cam cover gaskets, including the spark plug seals and the seals for the screws.

At the top left of the page click on 'User CP'. Find the signature section and give the model and year there.

 

A pic or pics would be nice....but like RJ, my initial assumption (and cheapest) would be the cam cover gaskets....and yes, please identify your vehicle more directly in your signature to better assist us.

 

it's xj8 I think I will change the valve cover gasket and the plastic camshaft tensioner.

 

While you have the covers off make sure you clean out the part load breather hose and the small orifice in the drivers side cam cover. Gaskets will fail with age but most of the time the failure is caused because of a partially blocked part load breather. The part load breather exhaust the crank case pressure to the throttle body. When the pressure builds up it will add to the cause of cam cover leaks.