Why is my 1990 Dodge Grand Caravan overheating?

Your cooling fan relay is not working. I bet your a/c doesnt work too well either huh? If it is not the relay then it is the fuse for the cooling fan. There is something not allowing your electrical cooling fan to come on. That is your culprit

If it were your thermostat you would see overheating in all driving conditions and not just particularly on hills and such. If the thermostat were going bad and sticking shut for example, you would see the temperature get higher and higher until you were forced to cut off the vehicle or until the thermostat finally opened and then you would see a very quick drop in temperature. It sounds as though your cooling system just may not be adequate for the conditions you are sometimes driving in (hills or stalled traffic and I am guessing using the AC in this weather). I am assuming that the radiator, water pump, cooling fans, and coolant condition are all in good order when I say that. If any of these are not in good order that may be the problem. A trick that you can use to help cool the vehicle when the temp is climbing (although not comfortable) is to turn off the AC and actually turn the heat on high. This pulls some heat off the engine/coolant.

If it were your thermostat you would see overheating in all driving conditions and not just particularly on hills and such. If the thermostat were going bad and sticking shut for example, you would see the temperature get higher and higher until you were forced to cut off the vehicle or until the thermostat finally opened and then you would see a very quick drop in temperature. It sounds as though your cooling system just may not be adequate for the conditions you are sometimes driving in (hills or stalled traffic and I am guessing using the AC in this weather). I am assuming that the radiator, water pump, cooling fans, and coolant condition are all in good order when I say that. If any of these are not in good order that may be the problem. A trick that you can use to help cool the vehicle when the temp is climbing (although not comfortable) is to turn off the AC and actually turn the heat on high. This pulls some heat off the engine/coolant

i would have tried the thermostat first in it,that's a lot cheaper than a new radiator,you need a new mechanic,if he replaced a radiator before he thought of replacing a thermostat,he needs to go back to school again,good luck with it.

The only thing that it would more than likely be is an air lock in the cooling system. While the engine is cold, remove the coolant pressure cap, start the engine and run it up to operating temperature and you should see air bubbles, once your happy that there are no bubbles any more than I think you'll be fine.

Why won't they change the thermostat just to please you?

There is also something I have experienced myself.

It is the temperature sending unit.

It can/will go bad.

It will give a false reading.

Have the ACTUAL temperature reading with a mechanical temperature Guage (mechanics should have one) and determine if your guage on your dash is correct.

Go from there and ask again.

good luck.

why dont you remove the thermostat and try again if you want to test it put it in a bowl of water bring to boil with temperature probe see if it opens smoothly and closes at the proper temperature

IT SOUNDS LIKE THE COOLING FANS ARENT WORKING PROPERLY BUT FOR GODS SAKE DONT DRIVE IT LIKE THIS OR THE WHOLE CAR WILL BE JUNK

ITS IMPOSSABLE FOR THE THERMOSTAT TO MAKE A CAR OVERHEAT ALONE THEY NEVER FAIL CLOSED THEY ALWAYS FAIL OPEN HOWEVER IF YOU DONT LIVE IN A COLD PLACE YOU COULD TAKE IT OUT TO ALLOW YOUR ENGINE TO RUN ALITTLE COOLER ITS AN OLD JUNK YARD TRICK

Could be a faulty thermostat

... they can come out of the box messed up.. especially if you believe your vehicle isn't actually over heating...

You answered your own question: It's a 1990 Dodge Caravan, for cripes sake!

Dodge=piece of crap!

1990=17 year old piece of crap!