Says ‘engines’ on the bottle
The boys grabbed a gigantic WD-40 bottle off the store shelf and turned it over to read the back. They figured they might as well learn something new that could help them with their quest while they were there.

The WD-40 bottle said “engines” on the back, leading them to believe that the product would work for an engine. Confident in this knowledge, they decided to try it out on one of their car engines.