Rotax 912 Oil Leak from Rear Exhaust Manifold

Update.

I’ve been definitely noticing oil seepage around the exhaust manifold and I am also getting some blackish oil droplets on my wheel pan that is on the same side and down stream from my exhaust.

I took the header off and used a borescope to investigate inside the exhaust manifold. It appears that I have an oil leak around the exhaust valve guide (See attached picture). I’m assuming the colder weather might be exasperating this issue (The oil seepage on the outside was due to the nuts holding the header onto the manifold took little to no effort to remove and I’m assuming were under-torqued).

Is this leak a problem that needs to be addressed immediately?

Hi Mauricio

The valve stem to the guide is lubricated by the oil vapor inside the cylinder head.  Normally this should be a very slight leakage with the oil residue burning off into the exhaust.  Excessive oil in this area is only one of 2 things, too much clearance on the guide or crankcase pressure is too high.  

Start by doing a crankcase pressure test, you can find that information in the installation manual.  if that is normal then pull the head and have a Rotax heavy maintenance shop check the guide to stem clearance.  It is unlikely it will mend itself.  

In addition be sure to check your exhaust pipe and the bore into the head.  If the pipe has been loose it may have worn the socket part of the head and need repair.  

Cheers