"tappet" noise

Unknown

I just received a super six through an inheritance, so the previous

owner cannot help. I have what today I would call a "stuck lifter", a

ticking noise, but I'm not sure from which cylinder. Anything to worry

about? Is there a cure? It seemed to appear when I changed the oil.

Also, there is an oil can under the hood, indicating something should

be oiled frequently. What is that for?