radiator neck
 

ok i know the S4 and S5 neck wont fit perfectly because the s5 has one more bolt to it, but could it fit and i could seal that extra bolt?? if i seal it, could the seal last with the heat from the motor??

s5 has a mount where the pressure cap goes. the mount wraps around the side of the fan shroud. I'm speaking of the driverside front fill neck on s5