A method of replacing radiator fluid in an automotive radiator includes providing two gas tight containers, a fluid conducting hose with a gas tight nozzle fitted into a radiator fill pipe nipple. The method further includes the steps of filling one of the containers with a fresh radiator fluid, drawing a high vacuum on a second one of the containers, drawing spent radiator fluid into the second one of the containers using only suction from the container, thereby leaving the automotive radiator under a partial vacuum and then drawing the fresh radiator fluid, from the first one of the containers, into the radiator using only suction from the partial vacuum in the radiator. A radiator flush step may also be applied following the same method, using two additional containers, one with initial high vacuum and the other containing flush fluid.