Lexus dealer states that ehater doesn't work due to manufacturer having installed contaminated antifreeze. They will repair car: my questions is what arts need repair/replacement and what potential roblems will emerge. Car has been driven 12 nmonths with approx 20k miles on it. Heater has not worked for 1 - 2 months.

Mosy likely they will replace the heater core. It looks simaler to a small radiator and when you blow air across it you get your heat for the car. If its clogged then it can't function.

Hey Bazz, what year 2010? What model RX350? Trying to see if there's service bulletins for this.

The car is a 2010 ES 350. What potential problems can develop in the years to come, assuming they replace the heat coil, radiator, hoses and thermostat, and flush the engine?

Your model comes up clean. No TSB's on this issue.
This is the first I've heard of any contaminated coolant.
You might be an isolated case.
I see no future problems as long as the job is done right.
At Lexus, only the best is expected. I understand your concern.