Originally Posted by rtg143

I would start with a new thermostat. If you intake is black in front and not aluminum, be very careful with tightening the bolts. They have to be tight but if the O'ring gets out of position it can crack the manifold. The manifolds will crack eventually if they're plastic. Mine is still plastic with 152k miles. You could have more than one problem, but lets get it to run at a normal temp first. That may take care of everything except the leak.

The fitting at the rear is metal bonded into the manifold. If the heater hose is not the culprit, the manifold is going to have to be replaced.