I gotta make a quick fix, close off the coolant return on the back of the commonblock 2.5 i have. I need to buy a cap to screw in. Anybody have an idea what size i need to plug the return hole? I dont have the hose off yet or il have a big mess. Gonna run the mitsu oil cooled until can get around to pulling it off and fixing the problem. Wna be able to drive to car without a huge coolant leak.