I sprayed some waterbased degreaser on the engine and hosed down with garden hose.*

Since then, car overheats and pops off the big hose on passenger side of the radiator, but radiator is COLD.*
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Example today: warm up under idle, drove 400 yards with some load: coolant temp went to 98C, yet radiator temp was 46C, fans not coming on.
I assume hose gets blown off because coolant is boiling, building lots of pressure.*

VCDS does NOT show any codes!

Since coolant is NOT flowing through radiator, I assume the valve (thermostat) is not opening.
Where is that thermostat (opening from small (engine) circuit to large (through radiator) circuit located on 4.0T engine?*