Additive to fuel tank

[Newsa]

I've heard there's a ball in the fuel filler spout. And I think it's partially preventing my standing additive from going into the fuel tank.

What's the best method to get the additive in without the additive spilling out the mysterious overfill valve hidden under the fender?

Do you stick the pump nozzle in there to push the ball down? And put the additive in with the pump nozzle in?

 

[Dieselnerd]

There are 2 flapper valves. Use the little funnel that's attached to your jack under the front passenger seat. That's what the funnel is for. Also needed if you want to add fuel from a can. A transmission funnel works fine too.