Engine additive
The crossword clue "Engine additive" is answered by STP, a 3-letter entry. Used 18 times across 12 distinct years; most recently in 2025; first recorded in 1994. It appears in 8 publications in the xd corpus. Every figure on this page comes from the collection data itself, never from a guess.
The answer
STP
3 letters. See every clue for this answer on the STP answer page.
Used 18 times across 12 distinct years; most recently in 2025; first recorded in 1994. It appears in 8 publications in the xd corpus. Frequency and last-seen figures come from the xd crossword corpus only.
Other answers for this clue
The same clue has also been answered these ways in the xd corpus. Answers inside this collection link to their own answer page.
- MOTOROIL (2 uses in xd)
Other clues for STP
Every other clue in this collection answered by STP, most used first.
- "The Racer's Edge" - used 88 times, most recently in 2026
- Fuel additive brand - used 70 times, most recently in 2026
- NASCAR sponsor - used 68 times, most recently in 2026
- NASCAR advertiser - used 42 times, most recently in 2026
- Gas additive brand - used 28 times, most recently in 2026
- Longtime NASCAR sponsor - used 27 times, most recently in 2026
- Motor oil brand - used 23 times, most recently in 2026
- Indy 500 sponsor - used 21 times, most recently in 2025
- Indy additive - used 15 times, most recently in 2020
- Octane Booster brand - used 15 times, most recently in 2025
- Oil-treatment letters - used 15 times, most recently in 2006
- Indy sponsor - used 14 times, most recently in 2025
- Indy 500 advertiser - used 11 times, most recently in 2026
- Indy 500 letters - used 11 times, most recently in 2020
- Motor oil additive - used 11 times, most recently in 2025
- Engine additive brand - used 10 times, most recently in 2026
- Indy letters - used 10 times, most recently in 2019
- Valvoline rival - used 10 times, most recently in 2026
- Additive sold at NAPA - used 8 times, most recently in 2023
- Car care brand - used 8 times, most recently in 2025
- Oil treatment brand - used 8 times, most recently in 2026
- 500 letters? - used 7 times, most recently in 2021
- Big name in fuel additives - used 7 times, most recently in 2025
- Letters at Indy - used 7 times, most recently in 2020
- Longtime Richard Petty sponsor - used 7 times, most recently in 2022
- NASCAR additive - used 7 times, most recently in 2022
- Oil additive - used 7 times, most recently in 2012
- Auto additive brand - used 6 times, most recently in 2025
- Big race sponsor - used 6 times, most recently in 2022
- Fuel additive - used 6 times, most recently in 2020
- Fuel additive letters - used 6 times, most recently in 2024
- Gas additive - used 6 times, most recently in 2007
- Gas additive letters - used 6 times, most recently in 2026
- Valvoline alternative - used 6 times, most recently in 2025
Related clues
Clues in this collection of the same answer length that share a word with this clue, or match its answer pattern when no word is shared. Most used first.
- Gun the engine - REV, used 168 times
- Gun, as an engine - REV, used 144 times
- Engine part - CAM, used 67 times
- Race, as an engine - REV, used 34 times
- Food additive - MSG, used 27 times
- Engine sound - HUM, used 26 times
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