Overheating on 1992 Lexus ES300

I have a 1992 Lexus es300 that starts and drives fine, but after the engine has been running for about 30 min. The car begins to overheat. Do you have any ideas what the problem might be?
Thanks

Asked by for the 1992 Lexus ES300
Clogged radiator, water pump, thermostat all could cause overheating have a shop diagnose this before it causes engine damage
2 answers 1 comment
I had this problem and got answers all over the board but what ended up being the problem were the two radiator caps. Replace both caps. Anytime that you open the cooling system it has to be flushed; do this by removing the overflow radiator cap (on the hose) and let the car run for about 15 minutes.
How do you flush the cooling system. Remove the back overflow cap and let run for 15 minutes? Is this the same thing as "burping" the system? I have so far replaced the thermostat, the radiator twice (due to overheating), the coolant temp sensor (the one on the block itself, no the one on the thermostat housing). I just now tried replacing the two caps.... keep my fingers crossed....