Yep...
You need to look under the intake with a flashlight, behind where the upper rad hose connects to the thermo housing...
Been there, done that...
Once upon a time, had the whole intake mani gasket replacement done, & since I was that deep, thought I'd replace the thermo too....ARGHHHHHH...
I nicked the O ring that comes off the back of the thermo housing, & didn't find out until I had torqued the intake mani bolts & fired it up....more
Tore it all down again, & since there were no O rings available at that point in time...goobered it up with some hi-temp RTV & let it cure over night...
Been to Moab twice on that repair, though I carry a couple of spare O rings, for when it eventually fails...
Have wrench - will travel!