I dont kinow volvos, but an engine is a engine at the end of the day.
Throw or break (I thow) a fan belt, that temp goes up real fast, coast 1/4 mile of the highway down the off ramp, keeps the rate of temp rise, bit not so out of control.
Close down the engine at the lights.. lights green fire up and turn onto a foot path park...this piont the engine getws shut down fast...
In my experiance, thats about the extreme limit for a engine with a few miles up on it, and not do damage, like warp a head...
1st check is hydrocarbbons/ COx gas test of the cooling system.
That checks out, full flush of the radiator, test the thertmostat in a elecrtic jug, and even if new.
I also noticed that the bottom radiator hose had also popped off.
Did u replace that?
What usually happens is it just gets put back on, and the reneforcing sprinfg inside is not checke to be in good condition...usually its long corroded away and gone and its non existance is not noticed lol
I dont think it relates here, as this usually effects hot highway driving at higher rpms, suck of the water pump, hose collaspses, slow down less such cools down.
Worth a check if havnt done so.