Yoon Lee

I know this Lexus technical photo is odd, but there are two cylinder block drain plugs. One locate in passenger side, other in driver side half bottom of engine. Correct step would be 1) flush radiator bottom, 2) clean reservoir tank, 3) unplug top and bottom hoses that goes engine to radiator, 4) drain engine block valves on the photo (Step 3, I done this job for waterpump + thermostat operation, you may not needed). To find two engine block plugs, https://www.my.is/forums/f221/is250-engine-block-coolant-drain-plug-location-463785/