I would be a bit nervous, just enough anxiety so you don't make a stupid move :wink: . I used marvels mystery oil "MMO", many of my friends recommended it, and it seemed to be less aggressive than ATF and Seafoam. More of a progressive cleaner that you run in your oil for a couple hundred miles, that does not do a shock and aw on your system. The vehicle I worked on was a 2004 Hyundai Santa Fe (my daily driver), which are notorious for developing ticking noises due to their crappy lifter design (they made the oil hole too small, and it easily cloggs). I ended up putting some MMO in (about 1 and 1/2 cups) the oil. Then put some MMO in the gasoline with a fresh tank of 93 octane (its rated for 87). I drove it 300 miles on the oil change and let it sit in there for a week. The ticking noise gradually subsided. The bottle says leave it in there until its time to change the oil again, of course they'd say that 8) . I changed the oil when it hit 300 miles (EXTREMELY BLACK) and I've never heard the engine run so smooth, sounded better than when it was new. Still sounds great a couple thousand miles later.
In your situation, I would use very little additive, and progressively flush the engine at every oil change. I will be doing this to my rover here shortly. I plan on using the same amount of additive, but only keeping it in there for 150 miles instead of 300. I will do this right before I change the oil, and about 5 times in a row, or at least until things start to shape up. After things start to sound better, I will probably drop the pan and clean out all of the gunk that is remaining.
. Ticks can be caused for a number of reasons. It could still be that your lifters aren't getting enough oil even though they are new. Although, I tend to agree with shupack, most likely the manifold.
