last night (ambient temp 85) car started overheating anytime I was at red light...temp gauge almost to red. I immediately popped on my heater full blast, as I was stuck in traffic. I noticed no heat coming out...hmm... when I finally was able to pull over, and it cooled down, I checked my coolant...empty! I put in water for the drive home, and had no temp issues. I've never seen a drop of coolant under the car, nor noticed leakage around overflow cap. nor have I noticed any unusual exhaust smoke...
ideas?
ideas?