EGR cooler question
 

looking for some insight on how exqactly the EGR cooler on the top of the motor works? im not an EGR guru, so im trying to figure everything out. i noticed it has coolant lines coming into the cooler, so if i get the EGR block off plate and an EFI live tune what exactly will that be blocking? will it keep coolant from entering? thanks for any help guys!