A DIP = KĄPIEL
the paint is applied by dipping of car body (or anything else) in a huge vessel filled with paint or coating.

GASOLINE RESISTANCE - the car paint finish must be resistant to gasoline, otherwise the paint would be gone in the area of refuelling inlet.

This is achieved with applying of an addtional layer of transparent coating.

Alternatively, your term may mean:
PRÓBA ZANURZENIOWA NA ODPORNOŚĆ NA DZIAŁANIE BENZYNY

A quality control process, when samples of painted material are dipped in gasoline and examined in order to determine their resistance to this agent.

Hard to say without the context.

Hope it helps, Kris.