95 v6
I recently flushed my radiator and i was wondering if anyone knows what the hell the bolt that reads, "remove before radiator refill" is?

Please respond because i cant remove the radiator cap for some reason so i was wondering if i am supposed to just refill the radiator through the bolt.
Any help is appreciated.

 

its to release bubbles in the system. when you add new coolante after a flush there is alot of air and that helps get rid of it.