Dragon Ball Z Episode 169: No Worries Here
Episode 169 of 291 of Dragon Ball Z, aired December 16, 1992, 25 minutes. Available with English subtitles and dub where released.
Episode summary
With nine days until Cell's tournament begins, Vegeta, Piccolo, and Trunks plan to return to the Hyperbolic Time Chamber. But Goku decides that he and Gohan have had enough training! What does Goku know that the others don't?