Ok guys - I have 76,000 on my 01 and while in Idaho yeterday I noticed that my coolant was done to the lower level - or the add portion. I added about 1/2 gallon. ????? What should I be concerned about? I can't seem to see any dripping,, ozzing or any wetness. Could I have a head gasket problem? Or has she just got hot and sent it out the overflow?