Our 2005 Liberty V-6 with 125K miles overheated in city traffic, but was OK on the road. I know the cooling system is in pretty good condition, but realized the thermostat had never been replaced. Not a fun job, but installed a new one and a lower radiator hose. Trickled water i until it came out of the drain valve. Attempted to close the valve and it BROKE! I see that O'Reilly Auto has a Dorman replacement valve. How do I get the old one out and the new one in? Hoping I don't have to replace the whole radiator. Having hand surgery next week, so I need to get this done. Really appreciate any and all help.