Hey mate, Depending on the engine you have will depend on where you have to fill the coolant up... who knows... might be the same as mine. My filler cap was right next to the engine block, on the top... between the spark plugs and intake plenum, to the left... metal cap. Having a proper seal on the caps are essential. All rad and filler caps can handle different amounts of pressure. For my 3VZ engine the rad tank uses a 1.1 compression and the filler is 1.0. Just so happens that the shop didn't have any 1.0s in stock so I got a 1.4 lol... stronger's better than weaker! I'd also be checking that there's no leftover blocks from any residual grit caught up in the radiator. Drain all coolant, get a hose, chuck it in either the top or bottom of the radiator and see if anything bad comes out... should be clear water. Fill up the cooling system a good 2-3 times with water, let the engine get to normal operating temps to allow the coolant to circulate... crank the heat up on the A/C for the heater core to open up... did it on mine 3 times and still had excess coolant :o hahaha I'd hit up the Toyota Long Life Coolant with some distilled water... seems to be the best for the Cammas :)