Billetworkz Engine Bay Caps – 2015–2021 Subaru STI

Tired of a boring engine bay? The Billetworkz Engine Bay Cap Set replaces crusty, faded factory plastics with precision-machined billet aluminum for a clean, custom look that instantly elevates your STI. These are direct factory replacements, CNC-machined from 6061 aluminum and finished in durable anodizing or powder coat (depending on color selection) for long-lasting style and OEM-level fitment.

Key Features

• CNC-Machined 6061 Aluminum: Premium billet construction for strength, longevity, and precise fit.
• High-Quality Finishes: Anodized or powder coated (based on color) for vibrant, corrosion-resistant color.
• Direct OEM Replacements: Installs in place of factory caps with no modification required.
• Cohesive Engine Bay Refresh: A matched set that cleans up the most visible under-hood plastics.
• STI-Specific Set: Includes the power steering cap to complete the EJ engine bay look.

Why We Like It

This is one of the fastest ways to make an STI engine bay look intentional and dialed. The caps are small but highly visible, and swapping to billet instantly raises the overall presentation—especially if you are pairing them with other premium engine bay upgrades.

Confirmed Fitment

• 2015–2021 Subaru WRX STI

Specifications

• Material: 6061 aluminum, CNC-machined
• Finish: Anodized or powder coated (varies by color selection)
• Fitment Style: Direct replacement cap set for 2015–2021 STI

Installation Notes

• Install with the engine cool and the vehicle on level ground.
• Remove OEM caps one at a time to avoid mixing locations.
• Ensure sealing surfaces are clean before installing new caps.
• Hand-tighten only; do not over-torque.
• After the first heat cycle, verify all caps are secure and leak-free.

What’s in the Box

• (1) Billetworkz Oil Cap
• (1) Billetworkz Wiper Fluid Cap
• (1) Billetworkz Coolant Overflow Cap
• (1) Billetworkz Brake Fluid Cap
• (1) Billetworkz Power Steering Fluid Cap

Compatibility & Disclaimers

Designed specifically for the 2015–2021 Subaru WRX STI. Finish color may vary slightly due to anodizing/powder coat processes and screen differences. Always follow OEM procedures when servicing fluid systems.