So this is my story that has a cycle to it. I fill up my coolant, once the car gets warm and i start driving my temp guage starts raising slowly, until it hits red line, than it starts makin like a raddling grinding noise somewhere from the engine and my belt squeaks loud and smoke comes from the coolant and engine. Also, the temp guage will reach its highest and stay like that for a while and than drop back down to the middle and will go back up to red line. To add on, oil color on dipstick is fine and also no white smoke comes from the exhaust.When I pull over and stop the car, the coolant is gone. Once the car cools off, the coolant is filled back up about a quarter way. What can this be???

 

Try looking under the engine while its happening.
Is the fan working while it overheats, is the grinding noise from the fan?
could be fan motor, tstat. radiator, those are the usuals. just got my lexus 2 days ago so I dont have any specific info for you.

 

if the fan still working, replace thermostat and radiator cap..