This billet oil cap replaces the standard plastic filler cap with a tougher, premium-grade aluminum alternative. Designed for longevity, heat resistance, and a clean look across any 4JJ build.

• Isuzu 4JJ1 — all variants
• Isuzu 4JJ3 — all variants (incl. MU-X & BT-50 4JJ3)

Direct swap using the OEM seal interface.

• CNC-machined billet aluminum construction
• Heat-resistant anodised finish
• Premium Thai design by HPD Special Parts
• Direct replacement for factory filler cap

• 1 × HPD Billet Oil Cap
• 1 × O-ring seal

• Remove factory filler cap
• Inspect seal; replace with supplied O-ring if needed
• Hand-tighten only — no tools required

• Anodised colors may vary slightly between batches
• Allow engine to cool before removing factory cap

• 💸 Buy Now, Pay Later: Afterpay, Humm, Klarna & Zip available
• ✈️ Free Express Shipping Australia-Wide
• 📦 Same-day dispatch on in-stock colors

Q: Will this fit both 4JJ1 and 4JJ3 engines?

A: Yes — it's a direct swap for all 4JJ1 and 4JJ3 variants, including MU-X and BT-50.

Q: Do I need to use the supplied O-ring?

A: Only if your factory seal is worn or damaged. Most installs reuse the OEM seal.

Q: Is this upgrade just cosmetic?

A: It looks good, but it's also far more durable than the OEM plastic cap.

Q: What colors do these come in?

A: Colors depend on the anodising batch — check stock options for availability.

Q: Does this improve engine performance?

A: No — this is a reliability and appearance upgrade, not a performance part.