A2QFI.
See my post #130 on page 7, burnt oil can only come from the rear of the engine, cabin air is normally taken from the compressor at the front of the engine, I wouldn't argue that the leaking oil isn't hot however.
The oil system is pretty damn complex in an engine and the oil gets so hot that it is necessary to cool it in what is known as a fuel-oil cooler. In addition the bearing compartments depend on localize pressurization (buffered air) to assist keeping the oil inside. This pressure has to come from the high pressured areas of the engine which are operating at temperatures high enough to fry an egg (try putting some turbine oil in a fry pan and see what happens). Now add some wear and tear to the engine oil seals and some of the fumes start leaking outside the bearing compartments as the engine changes speeds. Look at the bottom of a nacelle someday and you may notice what looks like a little pipe blowing smoke as you taxi arround. That's connected to the oil system. There is liittle you can do to seal an engine oil system from breathing oil.
The question is how much gets to the passengers and what is really too much. Zero is not practical.