Take it out and boil it for a while. That may make it swell back up. Clean the channel in the VC and the mating surface on the head real well. Use Permatex 518 Anaerobic sealer on the half moons.

 

It will probably break when you try to remove it. Just order some other stuff and get free shipping... like a case of oil filters or some coolant or something.

 

It will probably break when you try to remove it.

Possibly, yes; probably, no. I've never had one break, but I suppose it's possible.

 

You might also check NAPA or O'reilly's. They may actually have since that is a high use item.