Vehicle needs to purge all the air form the radiator. Jeep Grand

Start vehicle when cold. remove rad cap, start engine & put heater on (not defrost) and let it run for a while & top up rad as coolant goes down, to about an inch or 2 from top of rad. If you have electric rad fans, watch temperature gauge and around normal operating temperature or slightly above, they should come on for a minute or 2 then shut off. If not electric fans, just watch in top of rad for increased flow through rad, indicating thermostat has opened & coolant is circulating. Rev engine slightly every once in a while for 5 or 10 seconds just to help increase flow etc to help assist bleeding air out faster. Watch for increased flow in rad, 2 or 3 times at least, or listen for fan to go on & off 2 or 3 times before putting rad cap back on. As your doing this, keep topping up rad if it needs it. Make sure rad cap on all the way, check coolant return bottle level & add to mark if required, and you should be good to go. One of the things people forget to do the most, is to turn heater on while doing this, and that is usually what causes a lot of airlocks in the system, so don't forget that step.

Run engine normally while filling radiator. Leave heater on high heat. When engine temp reads normal, shut it off, wait about three minutes...re-start and complete filling.