So i just recently have my radiator replaced, Topped radiator off with coolant, with heater on high. I let motor run for about 10-15 minutes and notice temperature guage almost reach to hot but radiator fan has not turned on. The 2 plugs on the Radiator fan is plugged in, All hose are connected and recently changed my timing belt, waterpump. I assume that the fan would go on after it reaches the desire temperature so can someone guide me to the right directions? btw it is a 1998 lexus gs300 with about 180k

 

When Temp is just above normal or Above half way check to see if you have 12v on plugs!

 

Sounds like you didn't leave the radiator cap off while you ran the engine after the new radiator install. The purpose of running the engine with the heater on is to allow all the air trapped in the system to escape. If you leave the radiator cap on the air stays trapped in the system. When the engine is cold take off the radiator cap and let the engine run. As the coolant level starts to drop add coolant. You'll be surprised how much more coolant needs to be added.