Nissan Altima

I have a 2002 Nissan Altima 2.5S with almost 70K miles on it. I noticed their were spill marks coming from my radiator cap onto my radiator and bought a new cap. I still can smell coolant when I turn my car off and was wondering what that could mean? I also notice a mild ticking noise whether I'm driving, or idling and when I have my heater on in the morning, it heats well when I'm driving, but gets cool when I'm at a stop sign or light. Is this all the same problem? Or are there many things wrong that I need to get repaired?

Thanks for your help!