I have 2008 Chevy Equinox (v6, 217,000 mileage) and it is overheating after 10 minutes of driving. When it overheats there is a message “turn off engine”, if engine is not shut off get another message “engine power reduced”

I took it to mechanic and was told that intake manifold gasket, water pump, thermostat all should be replaced, does this sound right? and what are a chances that these recommended items wont fix issue, in other words is it worth spending $800 to do this job or chance that this will fix it are very small.
Reading through other posts i saw that there is high chance it maybe a head gasket...; is there a way to check if head gasket or other bigger engine issue failing without getting car to a mechanic (well i cant drive it there), wonder how much it costs.

 

If you have no confidence in the proposed fix the first thing you should replace is your mechanic. Good luck.