Q&A

just got this beauty and it needs a few things done but what to do first?? coolant temp climbs at stop lights but lowers at high speeds.
this was happening before my coolant overflow tank just cracked and is now leaking..is this a blown head gasket, bad water pump, or just possibly the fact the it may have frozen due to the 80% water:20% coolant my family member put in it instead of 25% water:75% coolant as the manual suggests??
I'm told the water may have frozen and then since the tank is old had then cracked when I turned it on because it couldn't handle the pressure.. maybe not any of the above but please help...dying to keep this beauty alive..