I too hear the clicking noise on my Spyder and often on my Lotus....it usually is a issue of type of oil...when you say at "normal operatating temp",does that mean say the car had been driven for a while, parked, then restarted when already warm and then you hear?.....If you can hear while the engine is running on the road, I would say you have an issue...but at idle, it happens to me all the time too.