Our 2001 Dodge Caravan is leaking coolant. Thermostat and radiator cap have been replaced. The upper and lower hoses are not leaking. We cannot see where the fluid is coming out of. It is dripping off the frame under the radiator mostly towards the drivers side of the engine compartment. Where do we look next to stop this leak?

The problem is the coolant isn't circulation through the system. You are getting all the pressure on one side of system and the tank is the only place where the pressure can be released. Is the thermostat good? Is it installed correctly? Check for coolant in the radiator. After vehicle has been running but turned off feel the upper radiator hose is it under pressure and hot. Next feel the bottom hose is it under pressure and cooler than the upper hose. If the upper hose is not under pressure fix thermostat it's not working correctly. If lower hose is not under pressure something is wrong with the radiator

To replace a thermostat in a 2001 Dodge Grand Caravan, look at the engine. Should be located at the engine end of the upper radiator hose in removable housing. Drain about 1 gallon of coolant from radiator Remove housing - make note how thermostat is installed Clean both surfaces Install new thermostat and gasket Re-fill coolant slowly to prevent an "air lock" Start engine check for leaks Run engine to normal operating temperature with heater on Check coolant level.------------------------------------------------------------------------------------------
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To replace a thermostat in a 2001 Dodge Grand Caravan, look at the engine. Should be located at the engine end of the upper radiator hose in removable housing. Drain about 1 gallon of coolant from radiator Remove housing - make note how thermostat is installed Clean both surfaces Install new thermostat and gasket Re-fill coolant slowly to prevent an "air lock" Start engine check for leaks Run engine to normal operating temperature with heater on Check coolant level.------------------------------------------------------------------------------------
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Always find the source first, The rear water ports are directly behind the rear lower intake bolts and the front ports are directly in front of the front bolts. The rear ports are cast into the lower intake manifold and are dead ends, air can get trapped in that area. In cold weather your thermostat may open slower, resulting in a pressure build up at the rear ports. Any trapped air will compress. Normal coolant system pressure occurs when the glycol is operating temperature. I would try refilling the system and getting the air out,the leak may only occur when the system is full. With a cold engine, open the radiator cap and add 50/50 mix, fill the resevoir to the low mark. Run the engine with the radiator cap off until the thermostat opens, the upper hose will be hot when the stat opens. Turn the car off and refill the radiator to the top. Sqeeze the upper hose to remove any air. fill if necessary. replace cap, run car again until it reaches operating temp. Now with a full system check for leaks. When replacing lost coolant should also have the heat at max temp. Get a good mirror to check for leaks. The outter mating surface of the rear water jacket gasket is flush with the block and the edge of the lower manifold, sometimes you can see where it blew out.

If it is fogging your windows, you have a leaking heater core. Dash removal is required to fix it.

Upper Radiator Hose and Thermostat

A large part of a radiator's function is made possible by the upper and lower radiator hoses. The upper radiator hose controls the flow of engine coolant from the radiator into the car engine. In a cold engine, engine coolant is stored inside the radiator. The engine coolant is held inside the radiator until the engine becomes hot enough to warrant engine coolant circulation. When an engine reaches operating temperature, the thermostat valve, which is located at the far end of the upper radiator hose, opens up and allows engine coolant to flow from the radiator into the engine.

Two big hoses attach to your radiator. Look for the one that goes back to the TOP of the engine. There is a housing with two bolts in it that the hose connects to. Drain radiator, remove hose. Remove the two bolts. Remove the housing. Thermostat is inside housing or still on engine. It just pulls out. Remove any remaining thermostat housing gasket material from the housing and the engine. Install new thermostat. Should only fit in one way. Install new thermostat housing gasket and the housing. Reattach hose and fill radiator, leaving the cap off. Turn on the car and wait until car gets to warm condition. You will see the water start to move from the radiator to the engine when the new thermostat releases at the proper temperature. Replace the radiator cap and clean up, you are finished.

This is how I like to do it. Make sure the car is parked with the front end at an upward angle. Drain the coolant from the petcock at the bottom of the radiator. Remove the upper and lower hoses at the radiator. Remove the thermostat housing, and the heater core hoses at the fire wall. Flush out the radiator by pouring fresh water into the overflow, and the hole where the thermostat was. Flush the heater core as best you can by pouring fresh water into the heater core hose connections.
Let all the water drain out, then button everything back up and replace the thermostat with a new one. Refill the rad and engine by filling the coolant reservoir with a mix of 50% water and 50% antifreeze, or buy the premixed stuff from the auto parts store. (Buy 4 jugs of premix or 2 of straight antifreeze)
Run the engine until it reaches operating temperature and the upper rad hose gets hot. Rev the engine a little to help get the air out of the cooling system. When the thermostat opens, the coolant level will drop in the reservoir, so top it up and replace the cap.
Check for leaks, and check the coolant level for the next few days, and check for leaks.
Dispose of the old coolant responsibly

the coolant should be right at the top of the radiator if you can see the bottom of the radiator that you have a stuck thermostat