Recently I had to replace a Cylinder Head because my original one cracked and was mixing oil with antifreeze. So I got a "new" one from a junk yard and installed it along with a brand-new head gasket. The oil mixing problem is gone but I'm having a loud clicking noise (Tick-Tick-Tick) in sync with engine RPM.

I suspected bad hydraulic lifter(s). Since my "new" head is actually used I decided to try the lifters from my original Head which did not make that ticking noise at all. That did NOT fix the ticking problem...

Next I took apart all 8 lifters from a "new" head (they all were full of black oil sludge). So I cleaned then re-lubricated then put them back in the engine. The problem got even worse: now I'm getting the same noise and also getting an unstable idle - like it is trying to stall...

What did I do wrong ? What test should I take to isolate ?

 

Are you sure the head is good? Did you have it checked out? I've got more than my fair share of bad heads from a wrecker. They don't exactly remove the bolts in the right order or at the correct relief.

 

I had this Head mailed from a junk yard some 300 miles away. It arrived very clean (they cleaned it) and without any visible damage or corrosion. Lifters, rockers and cam were included. So I just swap my bad one with a "new" one. Ever since I'm having that clicking noise whatever I do.