If you do have a slight oil leak I would'nt use synthetic because the leak will probably get worse (I would'nt use synthetic anyway). If it's just a drop every week or so maybe your drain plug or filter are leaking a bit. I would just keep an eye on it and check the level from time to time. If it goes away after the oil is changed and the plug and filter are replaced there's your answer. If not then I would look further.
Hope this helps!

 

Not a Jaguar recommendation anymore, but it was once upon a time. The fact is that if there is an oil leak, synthetic will definitely make it worse. I would change it with reg at least once more and make sure that the oil leak was because of a loose bolt or filter. If that was the problem, then use synthetic because it is better for heat dissipation(sp?), if that wasn't your problem, good luck because with only 25K miles there shouldn't be many problems, specially on the 3.0! Good luck and let us know how things went.

 

The dealer uses regular oil, it should be in the owners manual and after awhile synthetic being very thin can start to leak at a lot of the seals as they get older. Some people do use it though.

 

That's true, and that's why high-mileage engines shouldn't use synthetic.

 

I might be wrong but I thinkI read in the manual that you should not use synthetic oil on the 3.0..