About a month back I did a coolant flush on my parents 850, and ever since then I am having a reoccurring "issue." I have the coolant level (in the expansion tank) right, or just a little below, "max," and this is where it was yesterday before my parents embarked on a 180 mile trip. When they returned last night, the coolant level was inbetween "max" and "min," and this is where it sits this morning-though perhaps a tad lower this morning. If they drive 100 miles or less the coolant might go a little above "max," but only on longer distances does it drop. I have inspected the entire cooling system, and have found absolutely no leaks. The top of the expansion tank is dry, and has no coolant residue, so I can be certain that there isn't any coolant coming out of the top. Is it possible that coolant is simply "inbetween" somewhere in the system, and the level (in the expansion tank) will work itself out. I am going to have my father drive the car to work today, and will inspect it again this evening. Have a most wonderful Monday one and all :)