1994 dodge caravan 3.3 L . I replaced thermostat 195. filled rad , ran motor for 1 hour with cap off , no bubbles, put cap on , ran 10 min, temp in car low worm not hot worm.

Hi,just fill it up then leave the rad cap off when the water warms up the fermostat opens you will see bubbles and the water might go down top it up when you dont see anymore bubbles put the rad cap back on,run the engine up to running temp then let it cool down again then take rad cap back off and top up as needed and put rad cap back on job done,all the best.

if no air in the system from internal heater or other places
new thermostat and radiator cap
good firm coolant hoses

old school air bleed
you fill coolant system with motor running
heater on in the car and thermostat open
burp the hoses until bubbles are no more

if still no better
what about these possibles
faulty coolant temp sender
head gasket failed
clogged radiator
cooling fans not spinning fast enough
or not coming on soon enough

Replace thermostat.

ya, you put the thermostat in backwards

in my experience i would have just changed the head gasket instead of putting in a new motor

anyway there could be an air pocket in the engine or rad what i would do is

1 drain the rad by drain plug located at the bottom of rad on left or right side looks like a valve
2 start the car and slowly add 50/50 antifreeze to the rad
3 once rad is full open and fill coolant bottle
4 watch temp to see if it goes up to the high mark

if this does not help I recommend taken the car back to the place you took it to get fixed could be a head gasket problem

when your engine is hot,check the temperature of your rad,if you get more than 30/50 degrees difference between the top and the bottom of the rad,you need to have your rad professionaly flushed.If you have a digital laser it will out perform any other temperature testing tool.

Not unusual to get big airlock if heater (not defrost) isn't on during bleeding process. I usually start vehicle, top up rad 1 " or so from top,turn heater on , then watch temperature gauge & wait for fan to come on after I see flow through rad indicating thermostat opened.(Normal operating temperature)I let it do that about 3 times before I put rad cap back on, after topping rad up to about an inch or 2 from top. Then fill coolant return bottle, to proper level. It may be your problem, but if your temperature gauge goes way up past normal operating temperature, before you see flow in rad, then maybe a faulty thermostat is the cause.

You'll only see good circulation when it's at operating temperature & hot enough for thermostat to open, allowing coolant to flow through the system. Hope you had heater on (not defrost) while you were letting it run/circulate. I usually wait for rad fan to come on 2 or 3 times, before I put cap back on. Rad fan comes on to cool what just came out of engine when thermostat opened, so when you see good flow, you'll probably see fan come on shortly after.

Did you bleed the cooling system after refilling the radiator ? to bleed the system, fill the radiator with water and coolant. Run the engine until it is at a good temperature. Then turn off the engine and look for a bleeding screw at the oulet of the thermostat housing and turn it with a screwdriver counterclock wise. The trapped air will go out and coolant will start coming out. refill the radiator and repeat until only coolant comes out and no air.be careful not to burn yourself.

Pretty common on those. I used CLR and disconnected my heater hoses & with a small pump, I ran CLR only, through the heater core, and let it sit in there overnight, flushed it through again next day, back flush as well. re-connect hoses, run engine with heater on, and rad cap off until the rad fan comes on 2 or 3 times, then put cap back on, to bleed air out of system. Cleaned it out enough to get the heat flowing again. If you changed thermostat and didn't let it run with heat on, and rad cap off for a while as described above, then do that first, just to make sure you haven't just got an air lock in the system.