HPD Special Parts
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The HPD Top Exit Crankcase Breather is precision CNC-machined for clean, upward hose routing on 4JJ1 and 4JJ3 engines. Perfect for tight engine bays, custom catch can setups, or HPD alloy rocker cover installations where space is premium and clean lines matter.
👉 Need the matching -10AN adapter? Click here.
Engineered specifically for Isuzu 4JJ1 and 4JJ3 engines, this HPD top-exit crankcase breather provides an elegant solution for routing crankcase ventilation upward and out of the way. The CNC-machined alloy construction ensures precise fitment, durability, and a premium appearance that complements HPD alloy rocker covers or enhances OEM valve covers.
Key Benefits:
⚠️ Important Compatibility Note: Not compatible with factory top-mount intercoolers due to clearance interference. The top-exit design requires sufficient overhead clearance.
🛠️ 4JJ3 Installation Note: Requires 4 × 8G (4.2 × 16 mm) stainless steel screws for mounting (not included with breather). Order screws separately or source locally before installation.
This HPD top-exit crankcase breather is compatible with the following vehicles equipped with Isuzu 4JJ1-TC or 4JJ3-TCX engines:
* 4JJ3 installations require 4 × 8G (4.2 × 16 mm) stainless steel screws for mounting. Screws not included — please order separately or source locally.
💡 Pro Tip: If running a catch can setup, pair this breather with the HPD -10AN push-in adapter for proper sealed plumbing and professional presentation.
DIY Time: 15-30 minutes for experienced DIYers
Professional: Available at most diesel mechanics or 4x4 workshops
⚠️ Important: Ensure all connections are secure and properly sealed. Leaking crankcase ventilation can cause oil mist in the engine bay and potential running issues. Apply thread locker to mounting screws to prevent loosening from vibration.
Current Stock Status: Usually in stock and ready to ship. Some batches may experience 1–3 week delays due to Thailand manufacturing schedules.
If your order is urgent: Message us first to confirm current stock availability before ordering. We'll let you know exact dispatch timeframes.
Pre-order Options: If temporarily out of stock, we can arrange pre-orders with estimated arrival dates from our Thailand supplier.
Q: Will this fit both 4JJ1 and 4JJ3 engines?
A: Yes! This HPD breather is engineered to fit both 4JJ1-TC (2007-2019) and 4JJ3-TCX (2020+) engines. However, 4JJ3 engines require 4 × 8G (4.2 × 16 mm) stainless steel screws for mounting, which are not included.
Q: What's the difference between 4JJ1 and 4JJ3 installation?
A: The breather fits both engines identically, but 4JJ3 installations require specific stainless steel mounting screws (4 × 8G / 4.2 × 16 mm) which are not included with the breather. 4JJ1 installations typically reuse factory hardware or require different screw specifications.
Q: Is it compatible with the factory top-mount intercooler?
A: No — the top-exit design projects upward and will interfere with factory top-mount intercoolers. This breather is designed for vehicles with front-mount intercoolers or sufficient overhead clearance in the engine bay.
Q: Will this fit my HPD alloy rocker cover?
A: Absolutely! This breather is specifically designed to complement HPD alloy rocker covers, providing a complete HPD styling package. It's also compatible with OEM factory rocker covers.
Q: Does this work with the BT-50?
A: Yes, but only the 2020+ Mazda BT-50 which uses the Isuzu 4JJ3-TCX engine on the Isuzu D-MAX platform. The older Ford-based BT-50 (2011-2020) uses different engines and is not compatible.
Q: Can I run this with a catch can?
A: Yes! That's exactly what this breather is designed for. The top-exit design makes routing to a catch can much cleaner and more compact. For professional sealed plumbing, pair it with the HPD -10AN push-in adapter (sold separately).
Q: Do I need the -10AN adapter?
A: The -10AN adapter is recommended if you're running a catch can with -10AN fittings. It provides a proper sealed connection and professional appearance. You can also use alternative hose connections depending on your catch can setup.
Q: What size hose does this take?
A: The top-exit outlet is designed to work with the HPD -10AN push-in adapter, which accommodates -10AN braided hose (common catch can plumbing size). Without the adapter, you can use appropriate sized rubber or silicone hose with hose clamps.
Q: Can I vent this to atmosphere instead of a catch can?
A: Technically yes, but we don't recommend it. Venting crankcase gases directly to atmosphere releases oil mist and potentially harmful vapors. A catch can is the proper solution for capturing oil vapor while allowing clean air to vent.
Q: Is hardware included?
A: No. Mounting screws for 4JJ3 installations (4 × 8G / 4.2 × 16 mm stainless steel) are not included. You'll need to source these separately from hardware suppliers or order them when purchasing the breather.
Q: Where can I get the screws for 4JJ3?
A: Any hardware store or fastener supplier should stock 8-gauge (4.2 × 16 mm) stainless steel screws. Make sure they're stainless steel for corrosion resistance in the engine bay environment. Alternatively, contact us and we may be able to include them with your order.
Q: What tools do I need for installation?
A: Basic hand tools — typically a Phillips or hex driver depending on your screw choice. Thread locker is recommended. Total installation time is 15-30 minutes for most DIYers.
Q: Can I install this myself?
A: If you're comfortable with basic mechanical work, yes. It's a straightforward removal of the factory breather and installation of the HPD unit. Ensure all connections are tight and properly sealed.
Q: Do I need to drain coolant or remove other components?
A: No — this is a simple bolt-in replacement for the factory crankcase breather. No coolant draining or major component removal required.
Q: Why would I want a top-exit breather?
A: Top-exit design allows cleaner routing in tight engine bays, easier catch can integration, and better clearance from exhaust manifolds. It also provides a more professional appearance compared to factory side-exit breathers with messy hose routing.
Q: What's the advantage over the factory breather?
A: The HPD breather offers superior construction (CNC alloy vs plastic), cleaner routing options, better integration with catch can setups, and premium appearance. It's also more durable and heat-resistant than factory plastic breathers.
Q: Will this improve performance?
A: The breather itself doesn't add power — its primary benefit is improved crankcase ventilation routing and catch can integration. Proper crankcase ventilation (especially with a catch can) can help maintain engine cleanliness and potentially improve longevity.
Q: Is the alloy breather better than plastic factory unit?
A: Yes. CNC-machined alloy is significantly more durable, heat-resistant, and visually appealing than factory plastic breathers. It won't crack, warp, or degrade from engine heat over time.
Q: Is this genuine HPD?
A: Yes! Authentic HPD Special Parts manufactured in Thailand to HPD's quality standards. We import directly from HPD Thailand.
Q: What's the finish like?
A: CNC-machined alloy with anodised finish. The surface is smooth, corrosion-resistant, and has a premium appearance that complements engine bay modifications.
Q: Does HPD offer a warranty?
A: HPD products come with manufacturer's warranty against defects in materials and workmanship. Contact us if you experience any issues.
Q: How quickly will this ship?
A: Usually same-day or next-day dispatch if in stock. Free express shipping to all Australian addresses. If you need urgent delivery, contact us before ordering to confirm stock availability.
Q: What if it's out of stock?
A: We can arrange pre-orders with estimated delivery timeframes (typically 1-3 weeks from Thailand). Contact us for current stock status if your order is time-sensitive.
Q: Do you ship internationally?
A: Yes! Contact us with your location for an international shipping quote. We regularly ship HPD parts worldwide.
Q: Can I return this if it doesn't fit?
A: Items must be unused and in original packaging for returns. Please confirm compatibility with your specific vehicle and intercooler configuration before ordering.
Q: Should I buy the -10AN adapter at the same time?
A: If you're planning to run a catch can with -10AN fittings, yes — order the adapter at the same time to complete your installation. This saves a second order and ensures you have everything you need.
Q: Do you sell complete catch can kits?
A: We stock various catch can solutions and related components. Browse our catch can category or contact us for complete kit recommendations for your specific vehicle.
Q: What other HPD parts do you recommend?
A: If you're installing this breather, consider the complete HPD engine bay upgrade: HPD alloy rocker cover, HPD rocker cover bolts (Ti burnt or stainless), and HPD -10AN adapter. Creates a fully coordinated premium appearance.
Upgrade your 4JJ1/4JJ3 with HPD's top-exit crankcase breather. CNC alloy quality from Thailand.
