I just noticed this noise today. There has always been some slight valve chatter/tapping but the loud tapping noise in the video just started today. Any ideas?

http://www.youtube.com/watch?v=Gc7bdNyjGkA

 

Ive been using redline 5w30 for the past 5000 miles and I have 30% left on the MID. This is the first time Ive used redline and Ive always used mobile 1 5w-20 synthetic.

I checked the oil and noticed it was very low. I had to add 1.5 quarts to bring it to the top line on the dipstick. I cannot find any leaks. Is this issue redline related or is something else the problem? I cant ever recall having to add oil because it was low. This is the first time and it needed 1.5 quarts WTF

 

also, the oil that was in there was a very dark brown, almost black.

I just changed the oil and the filter with redline 5w30 again since I had 5 quarts here.