I did replace about half of it when I replace the valve seal. The best trick to remove the noise for me is to stop the engine briefly and then start is again.

I would not think there would be much gunk inside. I always use Mobil 1 since I got it at 72K 5 years ago.

I am sorry to hear you have soo much trouble with it. It never give me big problem although I tend to break more stuff whenever I tried to make it better.