Overheating its over heating after driving for 5minutes

May be heater core or the radiator has a pin hole in it..

The piston can only be damaged during the overheating condition. It is possible, and makes sense, that the damage to the piston was discovered during the test drive.

you are not in USA, so post country.
the harrier here is Lexus RX.
so not posting that , nor posting what engine is in car makes
all answers wrong.

generic answers.
1: get a tune up, (the operators guide has a list. the 60,000 mile (100km) column are the critical parts. as is any cam belt.

with heated? Signal , what signal?
what is that?
and if the engine is overheated , that is normal the jerking.
fix overheated cause.

Possible, with rad cap off, let vehicle idle until coolant fan comes on then shut vehicle off for 30 minute cool down. Top up rad, install cap and drive and recheck heater operation and any overheating.

Assuming the radiator fan works correctly, my guess would be a leaking head gasket.

get an ABRO radiator stop leak warm up engine for 5minutes open radiator filler cap slowly pour all content into radiator add up water to fill replace cap and drive.

Looks like you have air in your coolant.

your thermostat probably stuck closed.when you cooled it down,it opened again.change the thermostat.

this is a closed system. The coolant has to be put into the reservoir. However, I suggest that you have the system pressure tested and check your oil to see if you have any coolant in it. If the oil looks like chocolate milk then you might have a bad intake gasket or head gasket.