So I think I have a stuck lifter in the Regal. I did some research on Hydraulic lifters, and everything seems to make sense so far. I have a tapping noise in the engine that's been there for the last 20k some miles. I don't exactly remember when it got there; I just remember hearing it. Its not really audible at idle, but the moment you rev even slightly, you can hear the ticking. Since I've replaced the valves, the lifters are the last bits that could be at fault here.
How would I go about fixing this problem? I just dumped a can of seafoam into my crankcase (with 1500 miles on the oil) in hopes that this might alleviate the problem. Does anyone have any other suggestions? The engine also recommends 10W30, but I'm using 5W30. Should I try using a heavier grade oil? Or is my only option to replace all of the lifters? Is there a way to figure out which one is bad or stuck? These things are about $10 each, so I'd prefer not to have to replace all 12 of them.
Any help would be appreciated.