1999 Dodge Intrepid overheating?

[Grandpa ?]

I took the car to a shop they said they pressure tested system and found no leaks and said the head gaskets were ok. no water in oil either. Car heats up and boils out. The shop changed the Thermostat, to no avail. They suggested changing out the Radiator and water pump. I would like a little more than a guess. When I got it home. I noticed coolant inside of the car on driver side floor. I bypassed the heater core. Also when it was hot it leaks out of bottom of reservoir - I found a crack in reservoir - changed it. Still same problem but does not leak now. I did pull over when it was heating up and looked at the fans while the engine was on. only one fan was running with the temp about 3/4 way up the gauge. Any ideas as to determine the problem?