It started with my temp gauge jumping randomly to the red and then jump back down to 210 less than a minute later. So at this point I figured I just had a bad thermostat. But I was driving home the other day and the temp gauge was jumping like usual until at one point it stated for a long period of time. I pulled over and checked my fluids. I was a quart low on oil and a gallon and half low on coolant. I filled up the radiator and bled the system of all the air bubbles and it ran fine for the remaining thirty miles. When I woke up this morning there was a considerably large puddle of coolant. It appears to be coming from the pulley between the radiator and the engine.
I originally thought that the thermostat was bad, but once I had missing coolant that appeared to be all over the engine bay I thought it was a bad head gasket. But with it coming from that pulley does that mean I have a bad water pump?
If you have the 4.0 then I would check the gasket between the thermostat housing first. They are notorious for leaking. It took me 3 gaskets to finally get it not leak even though I cleaned mine perfectly. I ended up putting a very thin coating of high temp sealer between the housing and gasket and the gasket and head. No leaks!
If its not the thermostat housing then most likely the water pump gasket or water pump itself. What ever you do, DO NOT...repeat DO NOT let it overheat. If you do then you run the risk of blowing the head gasket and / or head...