Catch can dynamics

So fellas.
I have had a catch can on this 2021 Ram. My question might seem obvious, BUT…..
My oil level never goes down, never burns oil, always been an excellent truck, so how is it my catch can gets half full over time? Where’s this oily crap come from? Weird.

You may not be able to see a .1L or .2L change on your dipstick but .1L building up over a few oil changes will start to fill your can. And if its sludgy gunk, it may be full of other contaminants that wouldn't actually affect your oil level.

I clean out my CC every couple of OCI's and I have a few ounces in there every time.

It collects the junk in the vapor before it goes to the PCV valve an back into the system for recirculation to keep the environmentalists happy

Catch cans greatly assists in keeping ones throttle body and intake manifold clean.
The gunk buildup in those areas can really rob an engine of efficiency and overall performance.

If you're PCV valve is old and/or higher mileage might be a consideration to change it out as well.
Maybe even take off your throttle body and give it a really good cleaning, too

The other thing that some do (Meeee...lol) is to also remove the bypass hose that is right where your oil fill is that goes over your intake manifold and into your airbox filter assembly, and install a breather filter there.

This will also aid in keeping any additional gunky vapor from recirculating back into the system

I do love the environment, but I also like my engine to be happy and cleaner so it gives me the optimal performance I expect.

I suppose this is why my d_i-c T-a_t O - r charges my A_z - Z the ridiculous carbon tax he does..... lol

I'm pretty new to this RAM forum and have seen several posts about catch cans, seemingly only on the 5.7 hemis. What is this all about other than what is mentioned above? Without one I assume the oil (mist?) goes back into into the engine as designed by the engineers but why is there an issue to begin with? And does this affect the 6.4 hemi as well? I don't see posts on that. I cannot imagine that much blowby on a new engine.

CanuckRam1313 said:

The other thing that some do (Meeee...lol) is to also remove the bypass hose that is right where your oil fill is that goes over your intake manifold and into your airbox filter assembly, and install a breather filter there.

This will also aid in keeping any additional gunky vapor from recirculating back into the system

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Do you have a specific filter that you could suggest to install?

Mike Wenrich said:

I'm pretty new to this RAM forum and have seen several posts about catch cans, seemingly only on the 5.7 hemis. What is this all about other than what is mentioned above? Without one I assume the oil (mist?) goes back into into the engine as designed by the engineers but why is there an issue to begin with? And does this affect the 6.4 hemi as well? I don't see posts on that. I cannot imagine that much blowby on a new engine.

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It affects all engines, Brother!

One can do a basic DIY catch can...
Morimoto or Billet Technology (aka BT) have them as well.

I personally went with the BT version as I really like their product quality, ability to customize, and they have their "Z" bracket that bolts right into a stock threaded hole on the engine itself for easy and optimal placement of the catch can so you can easily access it for regular cleaning.

BT also regularly has amazing sales on their products, so it makes purchasing pretty much a no brainer as far as cost vs quality and customization goes.

New engine or not, the crud that blows by does cause buildup on the throttle body and inside the intake manifold. Over time this appreciably robs ones engine of efficiency and overall performance from a drivability perspective.

I've got a brand new Warlock and I just checked my CC and there is a small amount of residue on the bottom of my CC... this would have gone into and coated my TB and intake manifold


** EDIT

Moroso is also a fantastic option to consider as well.
They have an ingenious drain valve on the bottom of their CC's that makes dumping out the gunk inside a breeze.

Either way... employing the use of a CC is a really good way to optimize your ownership experience in terms of keeping the engine cleaner and happier!

MontanaHandyman said:

Do you have a specific filter that you could suggest to install?

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K&N is what I have.

Look up K&N breather filter and you'll find it

Thanks for all the replies!
To clarify, this is not an issue, my truck has only 22,880 mls and I suppose I clean it out maybe? every three months ( or when I think of it lol.

Moved from WI to NC and went from 11,000mls to 22,000 mls seemingly overnight!

This is all I got for that 10-12000 ml interval. And that is several empties!

Thanks again.

British Bulldog said:

Thanks for all the replies!
To clarify, this is not an issue, my truck has only 22,880 mls and I suppose I clean it out maybe? every three months ( or when I think of it lol.

Moved from WI to NC and went from 11,000mls to 22,000 mls seemingly overnight!

This is all I got for that 10-12000 ml interval. And that is several empties!

Thanks again.

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Maybe she needs allergy medication ?

It dosent do **** on my 6.4L intake but my 5.7L intake it would fill up.

In other words is a waste of money on the 6.4L intake were I live. YMMV

DILLIGAF said:

It dosent do **** on my 6.4L intake but my 5.7L intake it would fill up.

In other words is a waste of money on the 6.4L intake were I live. YMMV

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Somethings up with the way you plumbed it then.If it filled up the can with the stock intake,it's also gonna fill up the can with the 6.4 intake.Changing the intake doesn't change squat in the crankcase,it's still going to have the exact same pressures and blowby past the rings with either intake. Either check your can over,or the way you've got it plumbed,and whether you defeated the stock pcv properly.
Personally i don't think plumbing the suction side into the EGR plate is the proper way to plumb a 6.4 intake for a catch can.Ideally you want the suction side directly in the airflow path,perferably directly in behind the throttle body in the intake mouth. When you go to full throttle intake manifold vaccum drops,so you don't get any real suction when it's plumbed into the egr plate,where as if it's plumbed into the intake trac,you'll get a syphon effect when manifold vaccum drops,and internal manifold air flow past the port would still create a suction / syphon effect. That's why all pcv systems are plumbed into the airflow path,whether it's a carb or fuel injection system. I'd lay odds if you moved your suction side from the egr plate,up to the intake trac , an inch or two behind the throttle body ,(basically in the same spot Ma Mopar mounts them on the 5.7's and car 6.4's),you'd be back to having the same amount in the can as you did with your stock 5.7 intake.

My wifes 6.4 fills a catch can as fast as either my truck or 300C fills the same exact Moroso can.
All 3 of my Hemi's have this can on them

Mike Wenrich said:

I'm pretty new to this RAM forum and have seen several posts about catch cans, seemingly only on the 5.7 hemis. What is this all about other than what is mentioned above? Without one I assume the oil (mist?) goes back into into the engine as designed by the engineers but why is there an issue to begin with? And does this affect the 6.4 hemi as well? I don't see posts on that. I cannot imagine that much blowby on a new engine.

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The 6.4 uses an internal PCV,so you have to mod it's intake to make a catch can work,by drilling a couple holes and gluing in a couple brass elbows. Do a search on here for CrazyKids posts as he has a thread on how to make a catch can work on a 6.4.
The 6.4 is just as bad as the 5.7 in regards to what it spits out the crankcase in fumes and oil mist vapour

Mike Wenrich said:

I'm pretty new to this RAM forum and have seen several posts about catch cans, seemingly only on the 5.7 hemis. What is this all about other than what is mentioned above? Without one I assume the oil (mist?) goes back into into the engine as designed by the engineers but why is there an issue to begin with? And does this affect the 6.4 hemi as well? I don't see posts on that. I cannot imagine that much blowby on a new engine.

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To add to what @CanuckRam1313 and @Wild one said, a CC can benefit any engine. All engines have blow-by. By design this blow by gets routed through the PCV valve and back into the intake system to be burned in the engine instead of being released to the atmosphere. This residue can also be deposited anywhere inside the intake system that's downstream of where the PVC tube connects, and over time can build up. It's not going to hurt your engine, but if enough build up happens it can have a small effect on performance. Where this becomes an issue is with gasoline direct injection (GDI) engines, which inject gasoline directly into the combustion chamber. This blow by residue collects on the back of the intake valves and ports. If enough builds up it can have a big effect on engine performance. It can even cause the GDI engine to run poorly. Thankfully the Hemi is port injected and not GDI. So these areas around the intake valves are constantly being cleaned by the solvent action of the gas when it's injected into the intake ports. Lots of people believe a catch can is a waste of money on a port injected engine, and lots believe they are worth the cost if installing them. My suggestion is to do some research on your own if you're on the fence about getting one.

Wild one said:

Somethings up with the way you plumbed it then.

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Yeah ok buddy . There's only 1 good DIY to follow on this site.

DILLIGAF said:

Yeah ok buddy . There's only 1 good DIY to follow on this site.

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That doesn't mean it's right Ian. Common sense would tell you swapping intakes won't change anything as far as a catch can goes,so if you're not catching as much in the can now as you did with the stock intake,it's probably because of the way it's plumbed. Anybody with an eye and azzhole can figure that out
Take a look at where the factory plumbs the suction side of the PCV system on your old stock intake,and if you have a neighbour with a 6.4 Challenger/Charger observe where it's suction side is plumbed,then duplicate those same systems. Khristopher/CrazyKid was one of the first guys to fab up a catch can system,on the 6.4 manifold swap,but that doesn't mean he did it right,he's just a backyard mechanic like the majority of us on here are,so prone to mistakes as any of us are.
In the realm of adding a catch can to a 6.4 intake,it's best to duplicate the factories system
Picture of where the factory plumbs in the pcv on a 6.4 car.

British Bulldog said:

So fellas.
I have had a catch can on this 2021 Ram. My question might seem obvious, BUT…..
My oil level never goes down, never burns oil, always been an excellent truck, so how is it my catch can gets half full over time? Where’s this oily crap come from? Weird.

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2019 here. Same results. No oil usage on dip stick between oil changes. And I do take advantage of synthetic oil. I stretch the 3000 mile rule way past 6000. But that is a whole other subject I would not upset the oil gods and don't jinx you and me and ask why. LOL Shhhhhhhh.

Thank you for the detailed info. I understand now. BTW, on oil use, I previously posted that my new truck was down on oil and thought maybe it was burning it. Dealer added 1.5 quarts at 1,400 miles and now I'm over 3,000 with no drop on the stick. So as some mentioned, it was likely down from the factory. Must have bee a Friday afternoon build. That is one of the reasons I was so interested in the catch can postings.

British Bulldog said:

So fellas.
I have had a catch can on this 2021 Ram. My question might seem obvious, BUT…..
My oil level never goes down, never burns oil, always been an excellent truck, so how is it my catch can gets half full over time? Where’s this oily crap come from? Weird.

Click to expand...

In an otherwise healthy engine there are two major contaminate sources of engine oil: 1) fuel, and 2), moisture. Both of these explain why you might never see a change in volume on the dipstick. Fuel contamination tends to dilute the oil and actually increase volume (unless the engine is driven enough for them to evaporate out), while moisture produces a sludge which usually forms as the oil travels over cold(er) internal areas of the engine.

Your catch can is capturing and isolating these bad oil byproducts which why you don't see a noticeable change on the dipstick.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 108880 miles.