850 oil leak

Have an 850 GLT with about 100k miles on it. Have an oil leak that the
repair shop has not been able to fix. First, they replaced the
camshaft position sensor seal. Still leaked. Then they resealed the
rear cover plate at the rear of the cylinder head. Still leaked. Now,
they removed camshaft sensor and there was a puddle of oil sitting in
the bottom ring. They said it's very unusual (of course) and there may
be some problem within the camshaft. Does anyone have an idea what the
problem could be?

 

Yes, I had a similar problem. Make sure the flame trap is clean. If not,
pressure will build up from within the engine and blow out the seals. This
simple maintenance act has solved that problem for me.