Dodge Repair: Overheating, radiator cooling fan, radiator hose

Question
I've got a '93 Spirit that has recently begun over heating.  I changed the thermostat and thought the problem was solved as while the car idled, the gauge stayed on cool, and the car heated up inside nicely.  As soon as I pulled away for a test drive however, the needle spiked to hot and the defrost began blowing cold air.  I popped the hood to find coolant spilling out of the overflow tank's relief valve.  The lower radiator hose was hot, but the top hose was cold.
Any ideas?

Answer
Mike,
If the system is overheating, you should check the following,
1. If the ignition timing is off, it will overheat
2. Radiator cooling fan not coming on when engine gets warm
3. You may have a bum theromostat, if the rad hose is cool and the bottom one is hot. What I would do is remove the thermostat, add coolant, and see if this stops the overheating.
4. Also, if the impellers on the back of the water pump are bad it will not circulate coolant. Hope this somewhat helps..