Having my Carisma only a couple months (2000 GDI 1.8 AUTO 45000 miles ) the problem of the Carisma coking up internally around the throttle body and valves etc. worried me so I did a bit of research. The throttle body has been cleaned once already. so I do not want have to do it again or have to replace it. I have explored oil catch cans where the the PCV IS ROUTED THROUGH A FILTER OF SOME sort instead of the inlet manifold. Also where the the engine draws in clean air from just before the throttle body. I have blanked this off and fitted a small engine breather filter to the pipe . Even though the engine is drawing air off there is still a way for oil to get on the throttle body. This was proved as there was oil residue in the end of the pipe.
The PCV (positiv crankcase ventilation)valve was routed to a air compressor inline air filter I purchased with a engine breather filter fitted on the other side. This will act like a oil catch can instead of the inlet manifold. The inlet manifold was blanked off. Any oil will be drained off and disposed of appropriately. Would welcome comments