I think okie's right, there's moisture in that there cap. Vents should be checked.
Luv the grease myself, put it on almost everything exept for anything that runs a low voltage signal. It is an insulator and non-conductive.

 

AJBert, actually I am getting misfires. But I'm not completely sure it's because of the cap. Like I said in other posts, I'm dealing with the dreaded P0306. Been this way for a few months now. I've replaced all secondary ignition parts, new fuel pump, spider injectors and just yesterday, new lifters. I haven't done a compression test yet like I thought I would be able to do today so we'll see tomorrow.

This whole thing is just so frustrating.