Ok. I recently had to replace the radiator in my 02. Did all the proper process, had to replace the O rings in my previous replacement of aluminum elbows. Got everything back together. Filled radiator etc. Kept noticing losing fluid. I check with dry rags stuffed everywhere while running and then cooled. Nothing around the radiator or elbows, hoses etc.

Driving car, keep smelling fluid being heated and burned off.

Today, I noticed, finally, for goodness sake, that the fluid is coming from a space between the thermostat housing and the upper intake manifold. Check oil, no fluid in oil, just changed the oil a week ago, it looks good.

When I am facing the engine, the fluid appears to seeping out or from between the thermostat housing back towards the drivers compartment around/below the throttle body area. There is a space obviously from below that area.

Why would there be coolant fluid there? I took a napkin at lunch and soaked up the fluid and watched it while motor was running. it is definitely seeping from there.

HELP me please understand or diagnose the problem.

Am I about to have a full-blown head gasket issue? or what..

Here is a picture I took. Right in that open area above the thermostat housing

 

There is coolant flowing through the intake tract (LIM, UIM, TB) Is it coming out between the LIM and UIM? Could be the gasket at that interface. Another option is the UIM itself - is yours original? They can get warped due to EGR and cause coolant leaks (usually internal though).

 

So if it is internal, what all is done to repair that? Just replace the upper intake manifold gasket? or tear down to the heads?

 

That's the thing, you've got to pull it apart and see. At a minimum you're going to need to pull the upper intake (and I'd be prepared to replace it if its still original), but its not impossible that you'll need to pull the lower too if you find evidence of leakage down further when you get that far.
If it were me and the lower intake had never been off, I'd probably plan up front to do those gaskets too. You're already 90% of the way there at that point, its not much more work or money to do them also.

The thing is though, I wouldnt just blindly throw parts at it either. As you've got an issue, I'd take your time looking at the parts as you tear it down to try to figure out exactly where its coming from. You want to be sure the parts you're throwing at it will address where its leaking for sure.