Detail: I have just pruchased a Mazda RX8 , I have noticed that the dip stick has got a creamy scum on it. I have been told that this because of short trips and not to worry. there is no sign on the oil filler cap.
Solution: You dont have heads on this motor,its a rotary engine the water seals on the engine are gone,sorry you need to rebeuild or just put a sealer it may help for a few months , You might want to have the head gaskets looked at that means you are getting water in the oil it has nothing to do with short trips oil should be a brownish color no matter what or black when it gets too thin doe the car idle rough or have any white smoke ? , Hi, a 6ya Mechanic can help you resolve that issue over the phone in a minute or two. Best thing about this new service is that you are never placed on hold and get to talk to real repair professionals here in the US. click here to Talk to a Mechanic (only for users in the US for now) and get all the help you need. Goodluck!