Problem with losing antifreeze/coolant

[Zom]

98 explorer. 4.0 S.O.C.

I noticed that it is dripping antifreeze/coolant. It seems like it is coming from the radiator or possibly one of the hoses. What is strange is that while the radiator may not have much antifreeze/coolant, The reservoir tank is always full. Is it possible that the thermostat is not working?

[shorod]

If the radiator was not full when the leak started, it won't efficiently pull from the reservoir tank.

Find the leak, top off the system, bleed out the air, and things will probably work the way they should. Since you need to perform some repairs currently, this would be a good time to replace the thermostat and upper and lower radiator hoses if they are the originals.

-Rod

[Jacfourteen]

you may have a bad cap as well, this would allow the coolant to pass thru the overflow tube into the reservoir and overflow resulting in low radiator and full reservoir. Like rod said though I would change the hoses, thermostat, and cap while you have it open.

[rhandwor]

After you replace the hoses and thermostat watch closely for a few days the water pumps also leak at times.

[realmntwin]

I had the same problem on my '93. Except my leak came from the intake manifold, and i didnt know it until i tested the cooling system with a pressure tool. The tool screws into where your radiator cap goes, then you pump it to maybe 12 psi and the place of origin of your leak should be obvious. I'm just adding this so that you don't waste your time assuming it's the radiator, when it could be leaking down from a higher point like the water pump/timing chain cover/ intake manifold/thermostat/or even the engine head. Oh yeah make sure your system has water in it when you test, and you got enough parts out of the way to see the leak (alternator&bracket, belt, tensioner all help too).