Changing a radiator valve/TRV using a pipe freezing kit and without draining down the entire system - YouTube
Pipe Freezing Kit hire
Amazon.com: OEMTOOLS 24507 Professional Series Ethylene Glycol Antifreeze Tester,Tests Freezing Point of Antifreeze and Proper Water/Coolant Mixture : Automotive
OEMTOOLS 87045 No Spill Coolant Filling Funnel Kit with Coolant Tester, Near Universal Fit, Antifreeze Tester Automotive, Coolant Funnel Automotive - Walmart.com
Mercedes Radiator Replacement Kit - Nissens 2115003202 | FCP Euro