Related Clues:

• 'Noble' element
• Car fluid
• Burner fuel
• Explorer's need
• With 40-Down, H+, e.g.
• Fun time
• Car fuel
• Highway sign word
• It's in a certain range
• It may be noble
• Auto additive
• Idle talk
• Mylanta target
• Pretentious talk
• Helium, for one