Fseth...Just to clarify...the red buoy does not go down when I jiggle it the COOLANT LEVEL goes down when I jiggle the red buoy....like jiggling the buoy displaces air or something causing the fluid level to go down thus allowing me to add more fluid...does that make better sense? I am assuming topping off the expansion tank requires no more skill than just opening the lid and pouring in BMW coolant or distilled water...PLEASE ADVISE if I am doing this incorrectly...

I have noticed some dried salt looking residue on the expansion tank arounfd the neck where the cap screws on and a little where the top and bottom half of the tank meets...is that an indication that the tank is leaking??? I thought initally that there was a leak where the two halves of the tank are joined but if so it is tiny...I have tried turning the engine on and watching to see if the pressure of the running engine causes a leak but to no avail...although I only did it for a few seconds...as I have mentioned I am worried about damaging the engine itself...Aside from the low coolant level light the car has a few dead pixels (something I factored into the purchase price of the car) and a passenger side burnt out turn signal...being fixed as we speak...It drives perfectly the interior looks BRAND new and there are about three scratches on the exterior...you would NEVER know it was a used vehicle by looking...I have been wanting to buy this car for three years and I HOPE I am not going to be sorry!!!