Could they have missed something in cleaning the jackets. Are there small passages where gunk could have not been flushed if not I'm going with the radiator
There isn't anything inside an engine that could be left dirty enough during a rebuild to make it overheat.
This is a perfect excuse to buy a temp gun if you want one though.
Myself, I would grab the top radiator hose with my hand while it's hot, and then do the same with the bottom hose and make my determination from there.
If the bottom hose is way colder than the top one and the engine overheats that would tell me I either have a slow flow from the water pump or a blocked radiator.
If they were both about the same it would tell me I need a new or better radiator.
I learned to do things by elimination the old school way that doesn't cost money. :D
These days it seems people try to replace common sense and knowledge with cash and can't figure out why the money is gone but they still have a problem.
