Lifters

I change my oil regularly, one day one of my lifters started tapping. What can cause that to happen and what can I do about fixing it. Do you have to off the top of the engine to get at the lifters? Is there something you can to oil to rectify this. I welcome any suggestions.

Thanks in advance.

I had this once in my 68 Camaro-- run it hard and get a lifter tap-- I used STP oil treatment (consistency of honey) to thicken the oil and it cured it every time..you might try that before you dig into the engine--