I purchased the Prestone Flush 'N Fill Kit to flush the coolant system on my Chevy Malibu 2003, but I don't know how to install the Splash Deflector Tube since the radiator does not have a cap. Can I remove the cap from the surge reservoir and snap the deflector the on there? Otherwise, how do open the system to allow the flush to drain? I appreciate any help I can get. Thanks!