Tractor Repair: oil leak, timing, cover

Question
I have a Case 2390 with an engine oil leak just to the front of the fuel pump. The leak is so small that I never have to add oil between oil changes,but is very messy along the left side of the engine.Hope you can give me an idea how to correct this problem.
Thanks, Arnold

Answer
i don't know this tractor but i would wash the engine get it good and clean then run the engine get it up to working temp while keeping an eye on the engine to see if the leak appears this should make it easy to pin point where the leak comes from.Most likely its either the inspection cover at the front of the engine for injector pump removal,the timing cover gasket or the gasket on the injector pump.but washing the engine and running it should help you find exactly where it is