The ability of the Lexus Radiator to dissipate the heat generated from the engine operating is not something that should be taken for granted. The radiator on your Lexus consists of over one hundred small channels that are placed in a vertical fashion so the coolant can easily run through it.
The coolant that runs through the radiator is a combination of anti freeze and water. It is the water that has dissolved solids in it that once it is heated then cooled in the process of running the Lexus engine then turning it off, will fall out of solution depositing themselves in the radiator's channels. This will slowing but surely reduce the size of the channels and restrict the flow of coolant through them. This impairs the Lexus radiator's about to sufficiently cool the engine and dissipate the heat it generates.
To help resolve this buildup of solids in the cooling system on your Lexus, the coolant system should be flushed annually. This is more than just draining the old coolant out and replacing it with new coolant. By running fresh water through the system and discharging the old coolant out of the upper coolant hose when it leaves the engine, a majority of the solids that have deposited themselves in the coolant , including those in the channels of the radiator. This will help to your coolant system to dissipate the heat generated by the engine in a more efficient manner.
If this flushing of your coolant system is not done annually, your Lexus will have overheating problems and a large repair bill within a short period of time. These solids, once they are too numerous, cannot be removed by a simple flushing of the system.