I have 2001 s430 - I replace t-stat , and fan . Car overheats in trafic or when sits with rpm over 2000 . On the hiway driving everything is OK , once stop in traffic - temp goes up to 120. Fan works fine . please help

 

possible rad. when the car is hot feel the upper hose and also the bottom hose. both should be somewhat hot. but one shouldnt be hot and the other cold. also you need to feel the radiator or use an infrared thermometer and check the temps across the surface of the rad. should be warm all over. should not have cold spots like hot at top and cold at the bottom. are you sure that you purged all the air out of the heater system? if there is air in the system youll overheat. do you get heat out of the heater when you use it? you should, but make sure the air is out of the system open the cap and run engine for a bit at like 3-4 thousand fore a bit until heat does come out if you dont have heat. maybe also a bad coolant temp sensor. also are you sure the cooling fan is running fast enough to cool the engine?