when engine stopped use your hands to feel around the rad, see if all the fins are evenly warmed,
my experience was some parts of rad is not hot, it meant some cooling tubing is plugged, so the rad is only partially doing its job.
then u need a new or 2nd hand rad.
I've even put a 300d non turbo rad in a turbo.
if u need to do lots of hill, be prepare to turn on heater inside, atleast it wont cook your engine.

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