cant say i really know what the case is but i never really looked that hard into it as the hoist it was sittin on at the time is of the local skyline nut who jus happens to work at an exhaust place, he said he had not seen this problem other than when a breather hose is blocked, even though when he blew the hose clear there was nothing appearing to be obstructing it? as for the oil boiling i don think it would be that unless there are some real bad bearings and by that stage you would know there was a real problem.
also i dunno if there would be any difference between series one and seriestwo mine has the neo engine and its my first car with a hair dryer so don really know much bout em, i have always had bikes over cars and still do i jus wanted a nice wagon.
i will endeavour to find out as much as i can from local nutters an pm you if i find anything out.
cheers
oxford