Alright well, about a week ago I posted about my oil pressure dropping to 20-60, after wheeling hard for a few hours. In that thread, I stated that it ran like crap when the oil pressure was reading that. I now know why.

My temp guage is the only guage of mine that doesn't work. I wheeled hard again (high RPM 2WD in a giant field on my property) for a good 30 minutes or so. I noticed my oil pressure dropped again, and then started to smell my engine. I parked, popped my hood, and water seemed to be dripping pretty quickly out of what I beleive is my thermostat. (Back part of my engine, where multiple hoses meet, left of my valve cover, small plastic thing), aside from that, my radiator reservoir was coughing up water, and steam.

What is likely the cause here?

 

That leaking thing is your heater control valve. Thermostat is at the front of the engine under the top radiator hose.

Per cruiser54 do this:

Use the diagram below and just eliminate that plastic piece of junk. Plug the vacuum line to it with a screw.
Attached Images

 

Would that be causing the overheating as well? My 4.0 was not very happy with me. The water in the reservoir was boiling.

 

Yep. But there could be other cooling system problems. You have to fix that first off.