Air Oil Separator VS. Catch Can | Which Is Better?

Air Oil Separator or AOS versus a catch can? Which should you choose? In this video, I explain what an air oil sperate or AOS is and does, what a catch can is, and what the right choice is between the two. So if you drive a Subaru WRX or a WRX STI, or any other forced induction car, give this a watch to learn about how an AOS or catch can will help your ride!
I also talk about how AOS and catch can systems work, so if you have ever wondered, does a catch can work? I answer that!
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[@mattys3248]

Dude gets to the actual point at 5:00 in

[@danielfish101]

Thank you

[@oh4013]

Thanks

[@shakultra]

Thanks dude!

[@thelifeofpair]

W comment

[@carlitos4art]

Very detailed explanation of both systems! I was able to understand much more after watching this video! Thanks! Keep up the content, I enjoy watching your videos very much. Excited for the project car coming!

[@AutoEnthusiast]

Glad it helped! Thanks for the comment!!

[@MikhailJohnson1980]

The solution should depend on your engine.. some oil catch cans capture water and oil for some reason..and you don't want that re-introduced into the oil pan. The question is .. can you guarantee that blowback pressure only has oil or...the gasoline we buy have no contaminents. it takes 2 minutes to empty your catch can. Seeing what i have seen, catch can all the way for me as i want to monitor what s being captured

[@jeffstieren4474]

I agree with you 100%.

[@joshuacataldo2612]

I have a 2014 Chevrolet Camaro 2 SS, automatic. I've had an oil catch can on this car for about 8 months now. I have saved all the black weird smelling oil like substance from the catch can so far. As of today, I have just reached about a quarter of a quart of waste. GM States if I'm not mistaken, that I could be up to a quart of oil low every month. Nothing in the oil department has changed for me. I did actually pick up .3 mph since installing this.

[@moisesr7840]

With a catch can you can monitor your system, it gives you strong indicative which you would never get from any AOS, and you wanna address those issues. AOS suck in winter time, at Sub-zero temperatures. Also AOS work efficiently during engine temperature only when the coolant is hot enough to evaporate all these residue.

[@JesusRodriguez-or5uw]

You are absolutely right,my AOS gave me tons of condensation during winter

[@bertcopeland]

Thanks for your video.

[@AutoEnthusiast]

Thanks for watching!

[@bradgreen987]

Like my '16 wrx, my IAG air/oil separator was $400, and another $400 to have installed. An absolute must for turbo vehicles

[@robertcabrera6232]

There is one additional benefit to an AOS that's heated by the cooling system, and that's that it keeps water condensation from forming in the can from recirculating in the engine oil. An unheated AOS or catch can will both collect water from the blow-by. In fact, the majority of liquid that is captured by either device will be water that has condensed from the blow-by vapor. This is due to the naturally occurring humidity in the air in much the same way that water is captured in a drain valve on a compressor. The water that's collected in a catch can doesn't really harm anything other than filling up the can quicker, since it's being disposed of anyway. However, the water in a non-heated AOS stays in solution with the oil and gets recirculated into the engine where it will thin viscosity and cause corrosion on engine internals. Therefore it's important for anyone who uses their vehicle as a daily driver that plans on installing an AOS to only buy one that's heated.

[@jacobhendricks3556]

The Crawford aos for the 2.0l Subaru does not have a connection for your coolant. However it is right in front of the radiator and the tubes are tucked under the intake so I imagine that would moderately help with the froth. Thoughts?

[@tdro98]

Your thoughts on the grim speed aos ?

[@iglapsu88]

What would you recommend for a 2020 Mercedes Benz Sprinter that has oil leaking from the Intercooler Charge Pipes and possibly the hoses? Great Video! Thanks.

[@tentaq3296]

Meny people suggest AOS, such as Provent 200. But if you are in a cold climate i think catch can might be better. I haven't yet decided which i'm going to install on my om642 engine, either a Provent 100 / 200 or a catch can. Both should work great but im conserned about the water condensation in winter...

[@markiie12]

what about ND mazda miata. just naturally aspirated not planing on boosting. just street driving as my daily. should i try a catch can or Aos??

[@StreetSoldierUK]

I’m fitting a oil catch can to my BMW E61 30d M57 LCI

[@stephanebrun718]

Do you plumb the catch can after the PCV valve or ou get rid of the valve ?

[@georgebradley1672]

I don't think you addressed how the separated oil gets back into the engine.

[@kevinoneill41]

If you don't want to vent blowby directly to atmosphere send it to your catch can then out to atmosphere some people will add a small filter on the exit port or add a secondary catch can to besure you captured all the contaminants befor it reaches atmosphere. My cach can is low. Its on the frame of the truck. So I also added a oneway check valve for 4X4ing just incase I go throug any water. Same as my vents on my diferentials.

[@StreetSoldierUK]

I’m going to make a filter with a steel scourer, the one I got hasn’t got a filter just a baffle

[@paulmarsdensr1095]

I would go with the AOS. IAG makes the best one in my opinion. My Question is why is the OEM PCV system efficient?

[@AutoEnthusiast]

IAG and Perrin are definitely top of the list! Why is the PCV system efficient or inefficient?

[@robhall1757]

AOS IAG street, When installing it is there a way that you could install it wrong? Like air hose goes to one side of the car? Or the oil hose goes to the other side of the oil part, I hope it makes sense just a question I’m curious about

[@AutoEnthusiast]

100% possible to install them incorrectly, happens more often than you would think. Just watch an install video!

[@robhall1757]

What will the car do if it’s wrong

[@HandMadeWrath]

@@robhall1757 the system will run ass backwards

[@mcurielcatipay9535]

Hello. What AOS do you recommend to use for a KIA 2023 Telluride?

[@popeyeandy959]

I've got a Palisade and am interested in same thing, and how much of a chance that Kia/Hyundai void the warranty

[@the_bromies_podcast239]

y’all do not need that shit in your fucking telluride bro

[@raymon760]

Just vent to atmosphere 😂

[@francogiorgi9010]

I heard and that AOS systems aren't good in colder climates, is thus true?

[@peterlattimore6013]

Density of air. Condensation will occur inside of the AOS when the engine cools n the ambient air becomes colder etc

[@petermorton2869]

I have a Chrysler PT Cruiser & I have a lot of blow by going from 2 hoses from the each of the 2 rocker covers & one hose goes to the intake manifold & the other hose goes to the big air box where the air filter is & one time down the track I went & checked the air filter & I unclipped the top of the air box & I got a quite a big shock to see the air filter covered in oil & I ended up taking the whole air box out & throwing the air filter away in the rubbish bin & giving the air box a clean up inside the air box & I always had top up some engine oil in the 2 liter engine & these Chrysler engines in these PT Cruisers I found out later down the track that these engines are not the best of engines & yet Chrysler brought the best V8 engine of all time was the 426 Hemi V8 engine & couldn't go wrong with this engine & these 426 Hemi V8 engine ruled Drag Racing in 1959 & even to today's Drag Racing the engines on are made & built from the similar design as the 426 Chrysler Hemi V8 engine only a lot big V8 engine & these engines are for Dragg Racing Only & getting 12,000 to 20,000 Horsepower out of these engines & that is Truly Amazing & yet the 426 cubic stock standard Hemi engine pulled out 425 Horsepower & nearly 1 Cubic inch per horsepower & that is amazing engine & with a little more work on this engine & by adding a 671 Supercharger & you will getting a 1,000 plus horsepower no problem at all but you more serious engine work on this 426 Hemi V8 engine & bore & stroke the crankshaft & higher lift camshafts & Hi Performance Forge Pistons & rings with a bigger 871 Supercharger & on nitrogen oxide & you could up to anything like 2,000 to 3,000 Plus horsepower no problem at all & getting back to the PT Cruiser I don't have the money to do up this engine but it doesn't smoke out the exhaust pipe & it still goes well & yet it has a blow by problem & I'm looking adding a oil catch can to this engine & I will have to make up a mounting bracket before I can install a oil catch can as there is not much room in the engine bay to mount a oil catch can straight in & I got away to make a Aluminum bracket in place & then mount the Oil Catch Can straight in onto the bracket & it will be Very Strong Bracket Too & I will be using Silicone vacuum Hoses which would be far better to use as it can stand up to very high temperatures & also can handle a lot more pressure as well Kind Regards Peter

[@diallo1347]

Dumb question: Does an AOS void your warranty? It seems like it shouldn't because it protects your engine. Asking for a wrx.

[@stevep4236]

Funny if they void it because of this "mod", they want your engine to go to crap

[@RobHTech]

Does installing an AOS on a WRX void any part of the warranty?

[@luisloera1309]

Yes but they benefit when tuning the car to make more power than stock and helps with oil vapors

[@mbdulka]

AOS for racing class. Catch can for street. Dry sump instead of either unless not allowed by (racing) class or you're cheap :P

[@lncstr01]

You still need aos for a very high power and oil sensitive platform like a boxer

[@mbdulka]

@@lncstr01 What is high power to you? I use a catch can at 700 HP on my Subaru. I don't want to recycle any garbage back into my engine. I don't really have any blow by anyway as my engine is built correctly. An AOS is usually required for class racing, not the streets ... or for lazy car owners that don't check oil level often.

​@@mbdulka That was my thought too, i dont want that rubbish going back into the engine. Especially since some applications condense the moisture in the air and mix into the oils 😬 My old 964 did this and my current Mustang does it. I'll drain the can and have it analyzed for shits-n-giggles... Learning that a decent amount of water got into it gave me that sinking feeling in the gut. Maybe this happens because i mount my catch tanks near or in clean airflow. Thoughts? Otherwise i would absolutely not want that recirculating back into my oil.

[@petergilchrist2805]

why would you allow that crap oil back in the motor

[@bbcake001]

Its NOT an air its a carbon dioxide! This happen after the explosion in the chamber!!! So what makes you say its still an air?

[@fifiandmax]

It bugs me that America is still 50 years behind in catch cans. Baffles are almost pathetic when compared to fibrous filters. Also catch cans should have pressure relief valves as a safety measure. Look at what the Germans and Australia have done with systems like Provent, Bossvent and Flashlube catch can Pro

[@theaussienurseflipper.8113]

The maintenance you talk about, is crap you open a tap. Even if you did it once a week when you check your motor oil a couple minutes, us nothing. He opened the tab check you cool I will check the engine levels check the other levels and then close the tap. Why do you make it sound like a big deal. The other system 5X on the price, is that just the buy unit and then you got fitting it in?

[@williamnewman2959]

So from what I understand if you are staying stock there is no need for this mod. What is your take on that? It’s just money wasted? I have friends that don’t believe it is necessary.

[@markkenward7040]

If your engine is direct injected only, the benefit is that the sludge and oil being pulled into the manifold does not exist and does not bake and coke on your intake valves. If you are direct injected AND port injected, then your intake valves are being washed by the fuel mix., so it is less needed.