The Problem: Oil Vapor in Your 370Z Intake

The Nissan VQ37VHR engine in the 370Z is a masterpiece of high-revving engineering, but like all modern engines, it has an Achilles' heel: oil vapor contamination. Under hard acceleration or sustained high RPMs, crankcase pressure forces oil mist through the Positive Crankcase Ventilation (PCV) system. Instead of being burned cleanly, this vapor coats intake valves, intercooler cores (on supercharged setups), and throttle bodies with a sticky carbon buildup. Over time, this leads to knocking, reduced power, and eventually costly valve cleaning. A properly installed catch can intercepts this oil before it reaches the intake, keeping your engine running like new.

What Is a Catch Can and How Does It Work?

A catch can is a simple yet effective device that separates oil droplets from the crankcase gases. The can typically contains a baffle, a mesh filter, or a coalescing media. As the oil-laden air enters the can, it swirls and slows down, causing the heavier oil particles to condense and fall to the bottom. The cleaned air then exits through a second port that connects back to the intake tract.

There are two common configurations: closed-loop (air recirculates back into the intake) and vent-to-atmosphere (VTA). For street-driven 370Zs, a closed-loop system is recommended to maintain proper engine vacuum and pass emissions inspections in many regions. A quality catch can kit will include all necessary hoses, fittings, and mounting brackets.

Benefits of Installing a Catch Can on Your 370Z

While the factory PCV system meets emissions standards, it is not designed to handle the high crankcase pressures generated during spirited driving or track use. Adding a catch can provides several measurable benefits:

  • Reduces Oil Consumption: By recovering oil vapor that would otherwise be burned, you'll see a slight decrease in top-offs between oil changes.
  • Prevents Carbon Buildup on Intake Valves: Direct injection engines like the VQ37VHR are especially prone to coking on the backs of intake valves because no fuel spray cleans them. A catch can is one of the most effective preventive measures for this issue.
  • Maintains Optimal Octane: Oil vapor acts as a contaminant that lowers the effective octane of the air-fuel mixture, increasing the risk of detonation (knock). Cleaner intake charge means safer timing.
  • Extends Engine Life: Less sludge and carbon lead to fewer hot spots, reduced wear on piston rings, and longer intervals between major engine services.
  • Improves Throttle Response: A clean throttle body and intake tract allow the engine to breathe more freely, recovering lost horsepower that has been eroded by buildup.

Tools and Materials You’ll Need

Before you begin, gather the following items. Having everything at hand will make the job go smoothly and prevent multiple trips to the tool box.

Required Tools

  • 10mm, 12mm, and 14mm sockets with ratchet and extensions
  • Flathead and Phillips screwdrivers
  • Trim removal tool (plastic pry bars) to remove engine covers without breaking clips
  • Step drill bit (if mounting requires drilling into metal brackets)
  • Torque wrench (for snugging bolts to spec)
  • Safety glasses and mechanic gloves

Catch Can Kit Components

  • Catch can with internal baffling (recommend 3/4” or larger ports for the VQ37)
  • Mounting bracket and hardware (choose a bracket that fits your model year – some aftermarket kits are model-specific)
  • Approximately 6 feet of high-temperature oil-rated hose (often included, but verify)
  • Stainless steel hose clamps (4-6, sizes to match hose OD)
  • Optional: quick-disconnect fittings if you want tool-free removal for emptying

If you are installing a catch can on a 370Z with aftermarket intake or a supercharger, be prepared to source additional custom-sized hoses and adapters. For stock vehicles, most kits are plug-and-play.

Step-by-Step Installation Guide for the Nissan 370Z

This guide assumes you are installing a typical dual-port closed-loop catch can on a naturally aspirated 370Z. Always refer to your specific kit’s instructions, as hose routing can vary by manufacturer.

Step 1: Prepare Your Workspace and Disconnect the Battery

Park your 370Z on a level surface and allow the engine to cool completely. Disconnect the negative battery terminal to prevent any accidental shorts while working near electrical connectors. Remove the engine beauty cover by pulling upward on the front edge (it is held by two rubber grommets) and then sliding it rearward.

Step 2: Locate the PCV System Components

On the VQ37VHR, the PCV system has two main lines: one on the driver’s side (the main PCV valve near the intake manifold) and a second on the passenger’s side (the fresh air intake tube leading into the valve cover). The catch can will be installed in-line on the driver’s side PCV hose. Look for a black rubber hose that runs from the intake manifold to a hard plastic pipe near the back of the engine. The passenger side hose is typically larger and connects the valve cover to the intake tube.

Step 3: Remove the Factory PCV Hose

Using a flathead screwdriver, loosen the spring clamp on the manifold end of the driver’s side PCV hose. Gently twist and pull the hose off. Follow the hose to where it connects to the hard plastic pipe (often near the alternator area) and disconnect it there as well. Set the factory hose aside – you can keep it as a spare or reuse it if your kit uses the same diameter.

Step 4: Mount the Catch Can

Choose a mounting location that is accessible for periodic draining and away from hot exhaust manifolds or moving belts. Popular spots on the 370Z include the passenger side strut tower area, the firewall near the brake master cylinder, or using a fabricated bracket that bolts to an unused threaded hole in the chassis. Use the supplied bracket and bolts to secure the catch can. Ensure the can sits vertically with the inlet and outlet ports oriented upward. If you need to drill, use a step bit and deburr the hole to protect the hose.

Step 5: Connect the Hoses – Inlet and Outlet

Most catch cans have inlet and outlet ports marked with an arrow or “IN” and “OUT.” Cut two pieces of hose – one to run from the manifold port to the can’s inlet, and another from the can’s outlet to the hard plastic pipe that originally connected to the factory PCV hose. Route the hoses along the wiring harness or existing cable channels using zip ties to keep them tidy and away from sharp edges. Slip a hose clamp over each end before pushing the hose fully onto the barbed fittings, then tighten the clamps.

Important: If your kit uses a single inlet and a filtered breather instead of a return line, you are installing a vent-to-atmosphere setup. This will throw a check engine light on most 370Z models and is not recommended for daily drivers.

Step 6: Secure and Inspect All Connections

Double-check that all clamps are tight and hoses are not kinked. Reinstall the engine beauty cover by pressing it down evenly. Reconnect the battery negative terminal. Start the engine and let it idle. Listen for any vacuum leaks (hissing sounds). Spray a small amount of carb cleaner around each connection; if the idle changes, tighten the clamp further. Let the engine reach operating temperature and go for a short test drive.

Step 7: Initial Check and Drain Preparation

After the test drive, allow the engine to cool and inspect the catch can for any oil accumulation. A well-sealed system will begin collecting oil immediately. Mark the current level on the sight tube (if equipped) or on the can itself. This gives you a baseline for your maintenance schedule.

Common Mistakes to Avoid

Even experienced DIYers can make errors during catch can installation. Keep these pitfalls in mind:

  • Reversing the Inlet/Outlet: Some cans use a check valve or internal baffle that only works when flow direction is correct. Reversing can actually push oil into the intake.
  • Using a Hose That Collapses Under Vacuum: Standard heater hose may flatten when the engine pulls high vacuum. Always use reinforced oil-rated hose (the kit-supplied hose is usually adequate).
  • Mounting Too Close to Exhaust Heat: The driver’s side headers near the firewall can reach 400°F (204°C). Keep the can and hoses at least 6 inches from any exhaust component.
  • Forgetting the Passenger Side Crankcase Vent: On high-mileage or boosted 370Zs, oil can also be drawn through the fresh air intake tube. Consider installing a second catch can on the passenger side to capture that vapor as well.
  • Overtightening Clamps: Stainless steel clamps can deform or cut into the hose if overtightened. Snug them until they just compress the hose, then give another quarter turn.

Maintenance: How Often to Empty Your Catch Can

Emptying the catch can is as important as installing it. If the can fills completely, oil will be drawn into the intake just as if no can were present. During moderate street driving, check the can every 3,000 miles (or every oil change). If you drive aggressively or track the car, inspect it every 500-1,000 miles. To empty, simply loosen the retaining nut or unclip the bottom bowl (depending on your can design), drain the collected oil into a drain pan, and reinstall. Dispose of the oil properly at a recycling center.

Some catch cans have a drain valve that allows you to empty without removing the can – a worthwhile feature if engine bay space is tight.

Choosing the Right Catch Can for Your 370Z

Not all catch cans are created equal. For the 370Z, look for these qualities:

  • Baffling Design: Mesh or labyrinth baffles are more effective than simple empty chambers. Check internal photos before buying.
  • Port Size: 3/4” (19mm) ports match the factory hoses. Using larger ports can require adapters and may reduce condensation.
  • Drain Convenience: A petcock drain is easier to use than a bowl that requires complete removal.
  • Brand Reputation: Look for kits from companies that specialize in Nissan performance, such as Z1 Motorsports or Mishimoto. A well-reviewed kit from a forum enthusiast is often a safer bet than a generic eBay special.

For more technical details on PCV system design, you can refer to this comprehensive engineering article on PCV systems to deepen your understanding of how the catch can integrates with your engine’s breathing.

Conclusion

Installing a catch can on your Nissan 370Z is one of the most cost-effective preventive maintenance upgrades you can perform. It protects the engine from the long-term damage caused by oil carbon buildup, helps maintain peak performance, and reduces the frequency of expensive intake valve cleaning services. The installation is straightforward for anyone who is comfortable with basic hand tools and following a step-by-step process. By selecting quality components and routing the hoses carefully, you’ll enjoy a cleaner, more reliable engine for thousands of miles. As with any modification, verify local emissions laws before cutting into PCV lines – but for most drivers, a well-maintained closed-loop catch can is both legal and highly beneficial.