Found this stuck in the engine side of my rad dead centre. It was 1/2 way in so I pulled it out nothing appears to be leaking. Caused a 1/4 inch space in the fins. Any ideas as to what and where it belongs?

Thanks

 

Its a 2 clip! Comes after a 1 clip and before a 3 clip. Seriousely, it looks like it just got thrown into the space either by accident (hitting something spinning on the motor) or by someone getting funny with your car. If it isn't leaking I would keep it until you see something like it in there. Then look for one missing, you'll have it and you woun't have to buy a new one.