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What is an Oil Catch Can and Do They Work?

Should You Be Thinking about Oil Catch Cans for Your Car?

The oil catch tank, otherwise called an oil catch can is a simple device that’s fitted into your vehicle’s cam/crankcase ventilation system. Having an oil catch can reduces the amount of oil vapors that get recirculated into the engine’s intake.

Most of the time, you’ll only see these in modified vehicles. You are probably wondering, why do they have them and does it really work? If they are so great, why don’t the new cars come with them installed? These are all questions we seek to answer in this article.

What is an Oil Catch Can Good For?

We could get as detailed and technical about explaining this as you could imagine. Let’s break it down into a layman’s explanation and a professional commentary as well. You choose which one works for you.

Layman’s Terms

Your engine is volatile. It’s filled with fuel, hot oil, lots of forced air, as well as plenty of moving metal components. All of these work together to create combustion. If you don’t know what combustion is, it’s basically just a series of explosions.

While the combustion process occurs, most of the compacted gas gets expelled out through your exhaust. There is some left behind which makes its way into your crankcase instead. This is referred to as blow-by.

The stock crankshaft ventilation system is fitted to prevent buildup from the mist. The valve inside diverts that dirty air. With an oil catch can, you effectively separate the air from the oil. This filter sends the air back to the engine without the oil so it can continue feeding the vehicle.

The oil catch tank gets fitted to the crankcase’s breather system. You place it between the intake system and the breather outlet. When the vapors pass through the can, oil droplets, water vapor, and unburnt fuel condense. This causes them to settle in the tank. This process keeps them from ever reaching your intake and prevents negative consequences.

The best oil catch can comes with a filter inside. This might be a Brillo-type or fine metal mesh. This medium creates a larger area to allow those vapors the chance to condense. You will need to drain the excess oil that accumulates over time, but this is a simple process that only involves opening the drain plug.

Wow! That was the simple explanation. Are you ready for the professional version?

Technical Terms

In a typical four-stroke engine, the piston goes up and down four times per cycle. When it first goes down, the intake valves open to create a vacuum. This process allows the cooler dense air to come in for combustion.

During that same time, fuel enters the cylinder. Then, your intake valves close while the piston rises towards the top of your cylinder. The compression causes pressure build-up inside the cylinder.

This pressure becomes so high that a little air escapes through the piston and the rings. This air makes its way into the crankcase. Again, this is referred to as blow-by. As your RPMs rise, the amount of this blow-by also increases. If you have an engine with more cylinders, you can also expect more blow-by.

Let’s be clear for a minute; not all the air escapes or we would never have combustion. It’s just a small amount.

The crank itself turns inside the oil pan full of oil (obviously). While this keeps everything lubricated, it’s essential that there’s ventilation so there isn’t a build-up of pressure inside the crankcase. If a build-up occurs, you’ll face failure from the force. This, in turn, leads to lots of oil blowing out on the street.

The pressure coming from the crankcase goes back through the intake tract and isn’t made of just air. It’s also going to contain oil. This passes through your intercooler and goes back into the combustion chamber. Along the way, the oil coats everything from the intake manifold, valves, boost hoses, and intercooler. Because the temperatures are so high, the oil solidifies onto the valves.

So – What’s Happens After This?

Good question! The intake valves get caked with oil. In engines with port injection, this isn’t an issue because the gas is introduced prior to the combustion chamber. This allows it to flow over the intake valves. This action actually cleans out the valves and prevents the caking of oil.

In a direct injection engine, caked on oil causes many symptoms. These include:

  • Pre-ignition
  • Knocking
  • Lower fuel economy
  • Power loss

We know what you’re thinking now – you want to know why the manufacturers set it up this way. Honestly, there isn’t anywhere safe for them to revert the gas. Clearly, they couldn’t put it back into the atmosphere.

Your next question is – why don’t the automakers install the oil catch can at the factory? It’s hard enough to get the average person to change their oil, do you really think they’ll take the time to empty an oil catch can? Probably not.

By putting the oil catch can after the PVC, before the intercooler, you solve the problem. This allows a pure air mixture to go into the intake valves and intercooler. This also means you won’t have to worry about caking of oil and a decrease in performance.

Let’s be honest; having an oil catch can isn’t going to significantly increase your power or make awesome noises that turn heads. That’s why many people who modify vehicles overlook this essential piece of equipment. If they took the time to install one, they would find that the engine typically runs at the most power possible and is worth the extra effort.

Wouldn’t a Breather Do the Job?

If you don’t know what a breather is, it’s just a cap that attaches to the valve cover from the PVC end. Instead of allowing fuel back into the system, it relieves the pressure by allowing gases to evaporate through its filter. If you want to prevent leakage from the intake side, you’ll have to cap the intake off.

There are some downsides to this method. First, the engine bay is a dirty place. This method often causes a strong smell from the oil and raw fuel. In addition, the filters need to be replaced every time they become ineffective. With the best oil catch can, you’ll simply empty it when it’s full and then reconnect it.

How Hard is it to Install an Oil Catch Can?

The best part about installing an oil catch can is that the process is easy. You don’t have to worry about performing an aftermarket tune. This is great if you’ve already had the tune because you won’t have to change anything to conform.

In total, installation of an oil catch can should take you about five minutes. Just disconnect the hose and reconnect it. It doesn’t get much easier than that.

Buying the Best Oil Catch Can

When you’re ready to look for the best oil catch can, there are some things you should know first.Not every oil catch tank is the same. In fact, you run the risk of purchasing one that is straight out junk if you aren’t careful.

The biggest scam is purchasing an oil catch can that doesn’t have anything inside it. It should come with parts like a filter media and hose. It shouldn’t be an empty can.

Even if you get one with the hose attached, it might not be the level of quality you hoped for. Many of them won’t actually hold up to the vacuum pressure or heat of your engine compartment. It might melt or collapse which is a disaster. If the hose feels at all flimsy to you, we highly recommend purchasing a separate aftermarket hose instead.

The good news is that there are plenty of reputable companies that pride themselves on making the best oil catch cans. Look for parts made from companies such as Cusco, Mishimoto, and GReddy. They often come with drain valves and sight level checks, which make everything easier.

If, on the other hand, you wish to fabricate your own oil catch can, then purchasing one of the cheap options is perfectly acceptable. Just look for one you can open to insert the filter media of your choice. Make sure you put stainless steel mesh inside so it doesn’t rust and won’t burn. Otherwise, you risk shredding metal ending up in your engine.

Higher-quality cans won’t use steel wool at all but prefer to come with a baffle system. This also removes the oil from the oil-air mixture. We find these are better at separation and seem to be less messy.

We’ve picked five models we trust.

1. Cusco 9mm Universal Oil Catch Can 2L Capacity

Cusco is one of the companies we mentioned that you can rely on to provide high-quality oil catch cans. This manufacturer is based out of Japan and spends their time researching the latest technologies for performance products that improve the driving experience. If you look inside many of the fastest modified cars, you’ll likely find some Cusco products used in their car.

Their oil catch can doesn’t disappoint. This 9mm variety is specifically designed to trap the harmful elements from entering your intake system. This prevents unburned gasoline and oil contaminants from causing buildup inside the intake. Because it keeps your system clear, it naturally improves the performance of your vehicle.

Keep in mind that this is the most expensive product on our list, but it comes complete with everything you need for installation. You receive the hardware, hose, and brackets. Not only is the Cusco oil can polished and finished in their flagship blue color, but it also holds 2-liters of material.

2. GReddy Oil Catch Tank: 9mm Hose (600cc)

GReddy is another reliable brand that you’ve likely seen in Super Street Magazine and at SEMA. They are a leader in aftermarket performance parts, which is why you can trust them with your oil catch can. This one is priced slightly lower than the option from Cusco, so it’s a nice choice if you want the best oil catch can, but still want to save a little dough.

This super-light can reduces the amount of blow-by gas that enters the engine. In doing this, your engine burns efficiently and helps the engine oil to last longer. By removing the oil from your throttle and plugs, you can expect your engine to perform better as well.

This 600cc can sits vertically and comes complete with sharp-looking red fittings. Allow GReddy to catch that oil, blow-by gas, and moisture so your engine and intake can do its job.

3. Mishimoto Large Aluminum Oil Catch Can

Going even further down the budget, without sacrificing quality, you find this option from Mishimoto. This one comes in three varying colors so you can customize it to your car’s look. This tank prevents the harmful buildup of oil from your intercooler, piping, turbocharger, and intake manifold. By doing so, you don’t have to worry about lower combustion temperatures or reduced efficiency.

Your polished can comes as a complete kit. It contains your mounting bracket, clamps, fittings, mounting hardware, and hoses to make things even easier on you. This simple upgrade is the ideal way to increase performance and add a professional appearance.

What makes this option different from the rest is that it comes with a lifetime warranty. That adds value and shows pride in their product. If something were to go wrong, which it shouldn’t, you are covered.

It’s a lightweight, compact design and also provides a built-in sight tube for quick checks. This 30-ounce can also comes in a variety of colors from wrinkle red, wrinkle black, or polished aluminum for a truly custom look.

4. Vincos Universal 3/8″& 9/16″ 400ml Aluminum Oil Catch Can

If you need to prioritize your budget, there’s still an option available to you. This universal catch can from Vincos is made from high-quality aluminum for durability and strength. It’s an ideal option if you want the most performance out of your vehicle.

Preserve your engine life by keeping it clean and running its best. This premium oil catch can captures the moisture and oil from the blow-by gas which leads to sludge and carbon build-up in the engine and intake system. This fully TIG welded system comes complete with an O-ring gasket to ensure there’s no oil leakage.

There are also two ways to install this option. Because it comes with your air filter, you could apply it as a vented system. With the stainless steel screw-on breather and hose clamp, it doesn’t matter how you install it; the unit won’t come loose from vibration. What’s nice about this setup is that you can also clean it easily. You don’t need to remove it when it gets full. Simply unscrew the bottom of the reservoir and everything you need to clean is accessible.

5. Ruien 0046 Polish Baffled Universal Aluminum Oil Catch Can

This lightweight oil catch can is the lowest priced option that is still durable and long-lasting. It’s constructed of aluminum and is effective as well. You’ll be able to catch the moisture and oil found in the blow-by gas which leads to sludge and carbon build-up. By doing so, you’ll effectively increase the life of your engine and intake system, plus you should see an increase in performance.

Even if you tend to drive under hard conditions, you can rely on this oil catch can to protect your car. The system comes complete with everything you need to get started. You’ll have the can, hoses, mounting bracket, and clamps.

While it’s a universal fit, the company recommends having it professionally installed. As you can see from our instructions earlier, if you know anything about cars, that’s not probably necessary. Attaching this or any oil catch can should take less than five minutes and is pretty straightforward. If you can afford a system better than this, we recommend you upgrade. If this is all that’s in your budget, it’s a great start.

Final Thoughts

If you take the performance of your vehicle seriously and you want to extend the life of your engine, you owe it to your car to add an oil catch can to the equation. For the cost, it’s a no-brainer as an easy, affordable upgrade that anyone can perform.

With a nice selection of options to choose from, it’s easy to get exactly what you want. There are some model specific options on the market, but there are also plenty of universal choices, like the ones we reviewed. Take your car’s performance and efficiency to the next level and invest in the best oil catch can. You may just be surprised what this minor modification can do.

About Brian Jones

Brian Jones spent over 30-years at various dealerships as an ASE Certified Master Tech. These days he works with those dealerships to create quality automotive content while spending more time with his family near Dallas, TX. In his spare time, you'll still find him playing with tools, cars, and many other "manly" gadgets. Brian's passions include traveling, pickup trucks, and anything related to motorsports.