Do Oil Catch Cans Actually Work?

Proof That Oil Catch Cans Are Worth It For Direct Injection Engines

What is an oil catch can? Do oil catch cans actually work? What do oil catch cans do? Can oil catch cans prevent carbon deposit from building up on intake valves? This video dives deep into the world of catch cans, demonstrating how they work, what science says about PCV systems and valve deposits, a real world example thanks to Humble Mechanic, and finally the difference between cheap and expensive catch cans. We’ll look at the difference in features between a $25 catch can versus a $230 catch can, and whether or not the price difference is justified.

Oil catch cans are placed between the PCV valve and the port on the intake manifold, allowing for the can to remove any oil that would otherwise end up back into your intake manifold, which can cause deposits to form on the intake valves. This video will examine their effectiveness, and if they’re a logical solution.

Big Thanks To Humble Mechanic For His Help!

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[EngineeringExplained]

A lot of questions asking "why don't catch cans come stock on cars?" Lots of reasons here, but some of the most obvious: 1) It's another maintenance item, and customers have a hard enough time just keeping up with oil changes. Examples like AdBlue and water injection systems, come to mind, engineers try to develop solutions around customer maintenance. 2) If a customer neglects it, the catch can fills, and then you're dumping that oil into your intake; this is worse than doing nothing at all. Then it's a liability issue for the manufacturer. 3) Ideally, a proper engineering solution to prevent carbon buildups wouldn't require any effort on the customer's part. This is where auto companies will put their focus. "How do we prevent carbon deposits." There are companies that do much better than others with DI engines. Catch cans are not the only solution. If you have an engine that suffers from carbon deposit problems, a catch can is likely to improve the system, as demonstrated in the video.

[DirtyMike_n_theBoyz]

Pffft...all filters do is weigh your car down and keep you from buying useful upgrades like wheel spacers and carbon fiber gas caps.

[Emilthehun]

My srt4 came with a factory catch can. It was the intercooler 😂

[randywl]

I made an oil catch can for my antique Chevy S10. I purchased a 32 oz Ozark trail thermos from Walmart for 9.99 and I drilled two holes in it, one a couple inches up from the bottom and another a couple inches down from the top. It took a lot of effort, but I made a stainless steel baffle slightly above the lower hole. It was interesting fitting that piece inside and epoxying it in place, but it works quite well.
As far as a filter, I purchased a 3-pack of coarse stainless steel scrubbers from the dollar store and put one inside the thermos, just above the baffle.
A line from the PCV valve goes to the bottom hole and the return line at the top goes to the throttle body.
I'm fortunate that there's plenty of room for this larger than normal catch can. I wanted a large can to make it easier for the moisture and oil to settle out. With the stainless steel scrubber in there, any vapors have to pass through the stainless steel mesh. No need for any other fancy filtering.
The engine has 288 thousand miles on it. I was having some severe moisture issues which I thought was a head gasket leak.
It turned out to be my thermostat running 15° to cool, a much colder than normal winter weather, and the largest item was the oil filler tube o-ring was not functioning because it had hardened up over time. This allowed cool damp air to go directly from the oil filler tube to the PCV valve.
Since it wasn't sucking air through the vent tube on the opposing rocker cover, there wasn't much circulation. The moisture was building up inside the engine and up into the vent tube.
Once I sealed up that O-ring on the oil fill tube, my moisture issues went away because my PCV and the vent tube were operating as they were supposed to.
Initially I had to catch can on the vent side of the engine were all my moisture issues were showing themselves. After installing the O-ring the catch can have absolutely no residue in.... Nothing.
Because of that, I switched it over to the rocker arm with the PCV valve.
The catch can is collecting oil only. No water vapor whatsoever.
The other thing which surprised me was once I sealed up the O-ring and the PCV system was operating correctly, oil leaks from my engine virtually ceased with the exception of a tiny amount from the rear main.
If you have engine oil leaks, be sure to check your PCV system and make sure everything is operating correctly. A minuscule amount of vacuum from the PCV system can keep pressure buildup from forcing oil out of the timing cover and rear main seals. My engine is unbelievably dry now.
Over the years I rebuilt two engines, ported a brand new set of heads and installed larger exhaust valves and I've done all of my own automotive work for 50 years.
Unbelievable that I just now understand the operation of PCV system. 😞
The journey and the discovery of my problem is all because I googled oil catch cans.
I thought they were only for race cars. Nope, they need to be on every car.

[BigMack]

Well done, Jason. Several comments if i may. 1. Can a car owner check whether he really needs an oil catch can? I think he can. Simply by disconnecting both vent lines (most engines will have two such lines) where they enter the intake system, one can then use a cotton swab to wipe the insides of each pipe or hose. If the swab comes out wet with oil you will know that oil and other stuff are passing into the engine intake system, and a catch can will be a good idea. If the swabs come out perfectly dry then not much oil is getting back to the intake and no catch can is likely needed. 2. I suspect many car manufacturers are doing a better job today compared to ten years back of reducing oil and other stuff from venting back into the intake systems on their engines. Why? To enable the combustion process to be as efficient as possible and to reduce those wicked intake valve deposits. They are doing this by placing the features found in the better designed oil catch cans into their PCV systems to do the catch can job. My example: We have a Mazda CX-5 Turbo (gas direct injected). Though the PCV hoses were dry by the swab test, I put a catch can on the engine anyway. All it gathered was light amber-colored clear water. No oil floated on top of this liquid. Though I am sure a little oil was in this mix, I felt it was too little to make it of any consequence, and I removed the catch can. I believe the very canny (bad pun) Mazda engineers included in the engine's vent system an oil separator to capture that evil (in this case) oil and drain it back to the crankcase. We also have a 2018 Charger 6.4L Hemi. It is not direct injected. Nonetheless I have a catch can on that engine, and it does collect a small amount of fluid which contains some oil. I am quite confident, however, that when I put my right foot down the port injectors liberally wash those huge intake valves and, thus, deposits will never be a problem. I always enjoy your videos. Keep up the good work.

[Jabid]

How much oil can an oil catch can catch if an oil catch can can catch oil?

[franksinatra]

I've has the $25 one on my car for about a year and a half and have not been disappointed!

[winschmitt]

I recently installed the $25 can (by Evil Engineering sold on Amazon) on my new ‘22 Hyundai Veloster N. It came with a nice aluminum mounting bracket, two different sizes of screw in hose adapters, and some steel wool padding to use under the little baffle in the lid. This helps catch more oil than just the baffle itself. Also- I found out the dip stick screws into the bottom of its cap, and can vibrate loose in time, allowing the dip stick to fall into the can. I unscrewed the dip stick from its cap, and screwed it back together with a dab of loctite. Great video Jason! Thanx!

[AmaroqStarwind]

I didn't know that I needed one of these.

Fun fact: I actually really love maintaining equipment. I don't know why. There's just something super satisfying about restoring things to peak condition and keeping them there, especially with more and more things to take care of.

[kamranqutbuddin]

"All of my cars are either port injected, or they run on electrons or something" ahahaha

[julioperez]

I used a catch can in my 2005 350Z. The VQ35DE RevUp was notorious for burning oil. After I swapped the engine for an LS3 back in 2018, using the same catch can, I still haven't seen any oil getting collected. The LS3 has been a superb engine and a great upgrade for the money!

[rarsn]

For anyone interested in modifying a car, and considering a catch can, this is an absolutely awesome video. Also, big thanks for featuring the Humble Mechanic, yet another awesome Youtuber that I can subscribe to for more knowledge! (I'm seriously starting to overload on good information thanks to so many excellent Youtube channels.)

[lordhumungous]

They absolutely work. I just fitted one to my high mileage NA car yesterday. The difference is night and day. Oil was pooling in the intake manifold and the engine was pinging slightly at most mild load conditions. The engine was being fed oil mist, effectively lowering the octane of the fuel. The pinging is now gone completely!

[andypreston]

I installed a baffled catch can a month ago on my 1998 Ford (Mercury) Cougar 2.5 V6 with 52, 000 miles.
Engine is in very good order apart from a couple of vacuum leaks which are being rectified.
I only do around 3000 miles a year in it, and so far the catch can has stopped around 5ml of carried-over oil passing through the inlet.
I have disabled and blanked the EGR valve which prevents soot and carbon from further clogging the intake, especially when it blends with the oil vapour from the crankcase breather.
My can is identical to the $100 product on this the UK I paid around £20 for it and I am very pleased with it.

[gregkimura]

Great video explaining oil catch cans. My Alfa Spiders came stock with oil catch cans. They use a metal mesh membrane and the swirling motion drops the oil to the bottom of the can. There's a oil return hose at the bottom of the can. What great technology in an car designed in the mid 60's!

[karolmalinowski]

Glad that my BMW V8 already had an oil/air separator 20 years ago... But it's also BMW, so in order to change it I need to remove the timing chain😆

[jcpahman]

I happen to be using the cheapest option shown here, I bought mine prior to finding this video. I have a 2.0 GDI non-turbo motor in my KIA and have been very impressed with how much condensation it catches.

[Andy.Jensen]

2:33 "Now with port fuel injection on my
Auto-subtitles: "Now with port fuel injection on my ass mm" 0_o

[TrentusMaximus]

FYI: Inside the $25 OCC, you can unscrew the "baffle" under the lid so you can install different filters to suit your needs. Foam works well too.

[ghost]

A caution on using oil catch cans in winter: don't. Condensation increases, more water collects in the can and then freezes. This requires close monitoring to drain the can when it's hot, otherwise water will build up to a level where, when frozen, it will interfere with airflow in the PVC line. PVC pressure goes up and bad things happen.