Whats that noise coming from my 318?

Sounds like lifters not pumping up to me. Marvel mystery oil helps but it might not work, Just recently changed out all my roller lifters in my 318 because a few lifters were starting to go that had that type of noise. my roller lifters had over 100k miles on them tho but engines been rebuilt. Do what 67dart273 said and go from there. Another thing, unless something got sucked into the cylinder that's rattling you can take out the spark plug in that cylinder.