So my coolant filler neck is K.Oed

and i need a new one. But do i need the o-ring as well? Im not sure of what i should get.

Also, im assuming its K.Oed because fluid is coming out of it when i drive and my Temperature is reading pretty high but not at the max yet.

Any advice?

 

Get a used filler neck, new O-ring, and a new filler cap. Test your thermostat, check your coolant level in the radiator, also check your coolant level in the reservoir, be sure your belts are properly tensioned, if you get a chance... Pressure test the coolant system, and search a bit.