FuseTech
4JJ1 Billet Oil Cooler Upgrade - Fuse Tech
4JJ1 Billet Oil Cooler Upgrade - Fuse Tech
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🧊 4JJ1 Billet Oil Cooler Upgrade – CNC Billet Aluminium
One Cooler. Every 4JJ1. 2005–2020 | FuseTech
The oil cooler your 4JJ1 should have come with.
The FuseTech billet aluminium oil cooler replaces the factory unit on every 4JJ1 from 2005 through 2020 — early alloy rocker cover engines and later DPF models alike. Factory coolers are a known weak point on high-kilometre and worked engines: internal leaks put oil into coolant (or coolant into oil), and once a bearing has spun, the old cooler is full of metal debris that can't be reliably flushed. This CNC-machined billet upgrade fixes both problems in one hit.
⚠️ SPUN A BEARING? Replacing the oil cooler is non-negotiable on any bottom-end rebuild. Debris trapped in the old cooler will take out fresh bearings. Fit new — don't flush and hope.
| Spec Snapshot | |
|---|---|
| Construction | CNC-machined billet aluminium |
| Engine fitment | All 4JJ1 (2005–2020) • also suits 4JK1 2.5L |
| Fitment type | Direct replacement for the factory oil cooler |
| Use case | Leaking factory cooler, engine rebuilds, preventative upgrade |
| Brand | FuseTech Performance |
✅ Key Features
- 🧊 Billet Construction: CNC-machined aluminium — eliminates the cracking and internal leak failures of the factory cooler
- 🌡️ Improved Heat Dissipation: Keeps oil temps in check on towing, touring and tuned builds
- 🔧 Direct Replacement: Fits in place of the factory oil cooler
- 🧰 Rebuild Essential: The correct fix after a spun bearing — no debris carry-over into a fresh engine
- 🚗 One Part, Every 4JJ1: Covers 2005–2020, alloy and plastic rocker cover engines
🔧 Vehicle Compatibility
- Isuzu D-MAX – 4JJ1 (2006–2020, all variants incl. DPF)
- Isuzu MU-X – 4JJ1 (2013–2021)
- Holden Colorado RC – 4JJ1 (2008–2012)
- Holden RA7 Rodeo – 4JJ1 (2007–2008)
- Also suits 4JK1 2.5L variants
Note: Does not suit the 4JJ3 (2020+ D-MAX/BT-50). Message us with your VIN if unsure.
📦 What's Included
- 1 × FuseTech CNC billet aluminium oil cooler
Fresh gaskets and seals are recommended at installation — contact us if you need them supplied with your order.
🛠️ Installation & Requirements
- Direct replacement for the factory oil cooler
- Professional installation recommended — correct sealing and cooling system bleed are critical
- Replace gaskets/seals during installation; never reuse old seals on an oil-to-coolant interface
- On rebuilds, flush the oil galleries and cooling system before fitting the new cooler
- Contact us to confirm stock availability if timing is critical
🛡️ Warranty & Returns
Covered under our standard policy — see our Refund, Returns & Warranty Policy for full terms.
💳 Payment & Shipping Options
- 💸 Buy Now, Pay Later: Afterpay, Humm, Klarna & Zip available
- ✈️ Free Express Shipping Australia-Wide
- 📦 Diesel performance specialists — not general parts resellers
❓ Frequently Asked Questions
Q: Will this fit my year 4JJ1?
A: Yes — this cooler suits every 4JJ1 from 2005 to 2020, including early alloy rocker cover engines and the later 2017–2020 DPF models. It also suits the 4JK1 2.5L. It does not suit the 4JJ3.
Q: Why do I need a new oil cooler after spinning a bearing?
A: Bearing material ends up trapped inside the factory cooler's internal passages and can't be reliably flushed out. Reusing the old cooler on a fresh engine risks sending that debris straight through your new bearings. A new cooler is standard practice on any proper rebuild.
Q: How do I know if my factory oil cooler is leaking?
A: The classic signs are oil in the coolant (milky residue in the overflow bottle or radiator) or coolant in the oil. If you're seeing either, pressure-test the cooler before condemning head gaskets.
Q: Is this a direct bolt-in replacement?
A: Yes — it replaces the factory oil cooler directly. Use fresh gaskets and seals, and bleed the cooling system properly after installation.
⚡ PROTECT YOUR 4JJ1'S BOTTOM END
FuseTech CNC billet oil cooler. All 4JJ1 2005–2020. The right fix for leaking coolers and rebuilds.
Disclaimer: Common Rail Cowboys is not affiliated with Isuzu Motors or Holden. Installation should be performed by a qualified technician. Fitment verification and correct installation are the buyer's responsibility.
