How To Install Oil Catch Tank

So, you're considering installing an oil catch tank? Excellent choice! This modification can significantly improve the longevity and performance of your engine, especially if you're pushing it hard or running forced induction. Let's dive into why it's beneficial and how to install one properly.

Understanding the Need: Blow-by and Your Engine

To understand the role of an oil catch tank, we need to understand blow-by. During the combustion process within your engine cylinders, not all the combustion gases are perfectly contained. Some gases, along with oil mist, escape past the piston rings and into the crankcase. This mixture is what we call blow-by.

The crankcase is where the crankshaft rotates and the engine oil is stored. Without a way to vent this blow-by, pressure would build up inside, leading to all sorts of problems like blown seals and reduced engine efficiency. That's where the Positive Crankcase Ventilation (PCV) system comes in.

The PCV system's primary job is to vent this blow-by from the crankcase and route it back into the intake manifold to be burned during the combustion process. This is done for emissions reasons. While seemingly harmless, this recycled blow-by is far from ideal.

The blow-by contains oil mist, water vapor, unburnt fuel, and other contaminants. Introducing this mixture back into the intake system coats the intake valves, throttle body, and even the intercooler (if you have a turbocharged engine) with a sticky, oily residue. Over time, this buildup can reduce airflow, decrease engine efficiency, and lead to decreased performance. This is especially problematic in Direct Injection engines where the fuel injectors spray directly into the cylinder instead of washing over the intake valves which traditionally helped keep them clean.

How an Oil Catch Tank Works

An oil catch tank, sometimes called an oil separator, intercepts the blow-by gases traveling from the crankcase to the intake manifold. It's essentially a filter and reservoir designed to separate the oil mist and other contaminants from the air. The filtered air is then routed back to the intake manifold (in a closed-loop system) or vented to the atmosphere (in an open-loop system). The separated oil and contaminants accumulate in the tank, which you periodically empty.

Inside the catch tank, you'll typically find a baffling system or a filter medium (like stainless steel wool or bronze mesh) designed to promote condensation of the oil vapor. As the blow-by gases pass through this system, the oil particles cling to the surfaces, coalesce, and eventually drip down into the bottom of the tank.

There are two main types of systems:

Closed-loop systems: These systems maintain the factory PCV functionality. The filtered air from the catch tank is routed back to the intake manifold. These are typically preferred for street cars because they are emissions compliant and prevent the release of oily fumes into the atmosphere.
Open-loop systems (vent-to-atmosphere): These systems vent the filtered air directly into the atmosphere. They are typically used in racing applications where emissions are less of a concern and maximum crankcase pressure relief is desired. However, they can be messy and are often not street legal.

Installation: A Step-by-Step Guide

Now, let's get down to the nitty-gritty of installing your oil catch tank. This is a general guide, and the specific steps may vary depending on your vehicle and the catch tank design. Always consult the instructions that came with your specific catch tank for the most accurate information.

Tools and Materials You'll Need:

Oil catch tank kit (includes tank, hoses, fittings, and mounting hardware)
Wrenches and sockets (metric or SAE, depending on your car)
Screwdrivers (various sizes)
Hose cutters or a sharp knife
Pliers
Thread sealant (Teflon tape or liquid sealant)
Clean rags
Safety glasses
Gloves

Step-by-Step Instructions:

Safety First! Disconnect the negative terminal of your battery before starting any work. This will prevent accidental electrical shorts.
Locate the PCV Valve and Intake Manifold Connection: Identify the PCV valve on your engine. It's usually located on the valve cover or intake manifold. Trace the hose that runs from the PCV valve to the intake manifold. This is the hose you'll be intercepting.
Mount the Catch Tank: Find a suitable location to mount the catch tank. It should be easily accessible for draining and away from excessive heat sources like the exhaust manifold. Use the provided mounting brackets to securely attach the tank to the chassis or engine bay. Ensure the tank is oriented correctly (usually with the inlet and outlet ports facing upwards).
Measure and Cut Hoses: Measure the distance between the PCV valve, the catch tank, and the intake manifold connection. Cut the hoses to the appropriate lengths, leaving a little extra slack. Make clean, square cuts to ensure proper sealing.
Connect the Hoses:
- Disconnect the original PCV hose from the PCV valve and intake manifold.
- Connect one of the new hoses from the PCV valve to the inlet port on the catch tank.
- Connect the other new hose from the outlet port on the catch tank to the intake manifold connection.
Ensure all hose connections are secure and properly clamped. Use hose clamps to prevent leaks. For barbed fittings, you may need to use pliers to carefully push the hoses onto the barbs.
Secure Fittings: Apply thread sealant (Teflon tape or liquid sealant) to the threads of any fittings before tightening them. This will help prevent leaks. Do not overtighten, as this can damage the fittings.
Check for Clearance: Ensure that the hoses and catch tank are not rubbing against any other components, such as the engine block, exhaust manifold, or wiring harnesses. If necessary, use zip ties or hose clamps to secure the hoses and prevent rubbing.
Reconnect the Battery: Reconnect the negative terminal of your battery.
Start the Engine and Check for Leaks: Start the engine and let it idle for a few minutes. Carefully inspect all hose connections and fittings for leaks. If you find any leaks, tighten the clamps or fittings as needed.

Common Issues and Maintenance

Once your oil catch tank is installed, regular maintenance is key to its effectiveness and longevity.

Draining the Tank: The most important maintenance task is draining the catch tank. The frequency of draining depends on your driving style and engine condition. Check the tank regularly (e.g., every oil change) and drain it when it's about half full. Allowing the tank to overfill can render it ineffective and potentially damage your engine. Most tanks have a drain valve or a removable bottom for easy draining.
Checking Hoses and Fittings: Periodically inspect the hoses and fittings for cracks, leaks, or damage. Replace any damaged components immediately.
Cleaning the Filter (If Applicable): Some catch tanks have a washable filter element. Clean the filter according to the manufacturer's instructions. A clogged filter will reduce the tank's effectiveness.
Freezing Temperatures: In cold climates, the condensation inside the catch tank can freeze, potentially blocking the hoses or even cracking the tank. Consider using a heated catch tank or insulating the hoses if you live in a region with extremely cold winters.

Do's and Don'ts / Best Practices

Do use high-quality hoses and fittings designed for automotive use. Cheap hoses can crack or leak over time.
Do use thread sealant on all threaded fittings to prevent leaks.
Do check the tank regularly and drain it as needed.
Do make sure the tank is mounted securely and away from excessive heat.
Don't overfill the catch tank.
Don't use an open-loop system on a street car without proper ventilation and consideration for emissions regulations.
Don't overtighten fittings, as this can damage them.
Don't neglect regular maintenance.

Conclusion

Installing an oil catch tank is a relatively straightforward modification that can provide significant benefits for your engine. By preventing oil and contaminants from recirculating through the intake system, you can improve engine efficiency, reduce carbon buildup, and potentially extend the life of your engine, especially in high-performance or forced induction applications. While it requires some basic mechanical skills, following these steps and adhering to best practices will ensure a successful installation and a healthier engine for years to come. I highly recommend this modification for anyone looking to optimize their engine's performance and longevity.