Outer Limits 4x4 Board

My missus car just started to make the illusive "tick tick" noise when cold in the mornings. What the best stuff to use to stop it? All my pajs have had similar issues but some products work heaps better than others. Whats the go?

I put that Lucas oil additive stuff in the top end when i had the rocker covers off at one stage, it got rid of the tappet noise but since my car has been sitting for 4 months it has come back again.