Fix the cap!!! See if this solves your problem. I had a Vette that after you came in from using it, had the smell of anti-freeze but never any drips or water spots anywhere. All the clamps were tight. Well it was a pin hole in the top radiator hose that only released fluid when hot and under pressure. How it was found was, I went to check the
oil and opened the hood in 30 degree weather and saw the steam coming from the pin hole, if it weren't that cold I would of never found this problem. Start with the cap!!!
Bill K