Manifold Breathers

noJeepshere · June 14, 2017

I recently changed my stock intake over to an S&B CAI, and noticed the PCV's (both of them) were dripping oil. This would explain why it used a quart the last oil change... Then I read about the catch can or oil seperator (if I were to go through the work of adding one, it'd be a seperator) and got to thinking, what about blocking off the holes in the intake and putting a manifold breather on the ports on the engine? I would think not having oil and fumes being pulled out under vacuum would result in far less oil consumption, and a bit of oil and grime never hurt my feelings, especially under the hood. The only time the engine bay needs to look pretty is for the emissions inspector guy and on show cars. Also, this would result in a cleaner intake, since no oil would get in it, period. Is there anything with the computers and sensors that would have an issue with this? Or should I just get a seperator?

Sierra706 · June 15, 2017

While I can't speak to codes or issues you might run into, I don't think the EPA would be very happy with you. Plus your truck would smell like gas/oil.

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Paintor · June 15, 2017

According to my Airaid MIT instructions I am looking at both valve covers are piped to the intake tube to get fresh filtered air.....no vacuum.

Then he should be fine with 2 filter breathers. ...even keep the EPA happy.

Somewheres on this engine is this bugger.....that sucks crankcase gasses into the intake behind the throttle body where there is vacuum... and I bet its under that ugly intake manifold:

https://www.rockauto.com/en/catalog/chevrolet,2014,silverado+1500,5.3l+v8,3294345,exhaust+&+emission,pcv+(positive+crankcase+ventilation)+valve,5052

Think its there on the bottom right in this picture between the heads....$5.

http://www.lingenfelter.com/forum_lingenfelter/filedata/fetch?id=3869&d=1371590722

Paintor · June 19, 2017

I saw on a Corvette forum where a guy did this, and his filter breather stopping vaporizing oil coming out as it turned back into a liquid on the inside of his filter and dripped back inside the engine. He effectively created a one way valve for his PCV system to actually work....

So I'm ordering these and putting them on my valve covers......oil catch cans.....screw that!

https://www.summitracing.com/parts/knn-62-1000

mookdoc6 · June 19, 2017

You going to throw codes most likely......and a mess! You will certainly have a mess!

camcamaro1991 · June 22, 2017

I recently changed my stock intake over to an S&B CAI, and noticed the PCV's (both of them) were dripping oil. This would explain why it used a quart the last oil change... Then I read about the catch can or oil seperator (if I were to go through the work of adding one, it'd be a seperator) and got to thinking, what about blocking off the holes in the intake and putting a manifold breather on the ports on the engine? I would think not having oil and fumes being pulled out under vacuum would result in far less oil consumption, and a bit of oil and grime never hurt my feelings, especially under the hood. The only time the engine bay needs to look pretty is for the emissions inspector guy and on show cars. Also, this would result in a cleaner intake, since no oil would get in it, period. Is there anything with the computers and sensors that would have an issue with this? Or should I just get a seperator?

btw, your factory setup would suck oil into the intake adding the CAI makes no difference other than inferior parts used. Blocking off the PCV system is just dumb, you want to be able to pull vacuum on the CAI side, breathers are not ideal as they vent to atmosphere which is a no no.

At idle the LOMA to intake manifold PCV side is at its highest vacuum, as you open the throttle blade the vacuum shifts to the valve cover to CAI connections and things begin to equalize .

I use a oil CC on my truck, it works fantastic, oil CC T's into the original system LOMA to intake manifold, obviously if you have a 5.3 or 6.2 the PCV line will mount differently, I did not use a CCS as the GEN 5 engines do have a type of CCS catch system in the valve covers.

Paintor · June 24, 2017

There is no vacuum being sucked by either the front left or right valve cover piping to the intake tube.

There is no vacuum what so ever....in front of a throttle body.

Both hoses are only clean filtered air intakes......

Throw codes? Explain how.

Jimmy W · June 26, 2017

not good for engine I would think

noJeepshere · July 10, 2017

There is no vacuum being sucked by either the front left or right valve cover piping to the intake tube.

There is no vacuum what so ever....in front of a throttle body.

Both hoses are only clean filtered air intakes......

Throw codes? Explain how.

While there is not "vacuum" in terms of the kind of vacuum you find downstream of the throttle body, Bernoulli's Prinicple dictates that movement of air creates a low pressure, thus sucking air through the manifold breathers into the intake tract, and all that comes with it, including engine oil that ends up contaminating the intake runners. Hence why these oil catchment systems are being used and even installed by dealers in many cases. Heavy duty diesels usually have a hose that runs from the top of the valve cover(s) down below the oil pan, where the fumes are vented to atmosphere.

There are no electronics involved, as far as I know, but this is a new platform for me to toy around with so I was doing intel gathering, hence why I asked if there would be any codes.

Static · July 10, 2017

Isnt this basically what the CSS does? loops the two valve covers together and block off on the the ports on the stock intake box and then you pull air theoretically through the CSS? Correct me if I am work but are we trying to reinvent the wheel here? If I am correct in my thinking then I am left wondering why you would want manifold breathers for any reason other than cost and if you are willing to spend $40k+ on a new truck why would not just drop the $100 for the CSS?