Instead of catch can, why not delete PCV?

SquireSCA · August 19, 2019

I guess my biggest question is... How much of this is FUD/Hype and how much of this is a real, valid concern?

I get that the catch can companies help promote this notion that all new cars and trucks have motors that will wear out and break down without the use of their products... But is that really true?

I have read about how the warranties were reduced and the assumed reasons why... But you would think that if this was going to cause premature wear, which could impact warranty claims but more importantly, brand image... If the "Longest lasting trucks on the road" image becomes, "Good for a year or two at best", I can't see how this won't cost them big time in the end... These companies tend to be strategic and you would think that if this was the case, they themselves would just have an OEM crank out some catch cans that would cost $50 each to the automaker and have it be a periodic maintenance item just like oil changes...

SquireSCA · August 19, 2019

I mean, a couple of these would do the job, I would think. It's what they are made for:

https://www.amazon.com/62-1600RD-Vent-Air-Filter-Breather/dp/B009774GCA/ref=sr_1_7?keywords=crankcase+vent+filter&qid=1566229385&s=gateway&sr=8-7

EXSlider400 · August 19, 2019

I did the catch can thing on a gas DI 1500 and yea it caught oil. I would rather no emission control for longevity but that is not going to happen. Now with the gas DI I am considering a throttle body cleaner every oil change instead...which may hit cats and O2 sensors though. There is no win here. Just keep in mind water is also in the return oil so in cold climates may freeze and create pressure.

SquireSCA · August 19, 2019

Well, I ordered two of those washable vent filters from Amazon Prime for $15 delivered tomorrow. I will install those, cap the holes in the Airaid MIT where the hoses formerly connected, and have them do a BG Products valve cleaning at my next oil change(20k miles) and monitor it from there. I will make sure that whatever I do, it's easily reversible... in case it doesn't work as I hope.

Grumpy Bear · August 19, 2019

1 hour ago, Donstar said:

Interesting topic!

Oh yes it is. The OP is taking things back several decades to the days of 'road draft tubes'. 40's/50's Pretty sure many on this site believe a PCV system is about 'pressure' when it is actually about lubrication. Pressure is secondary. Required yes but secondary.

Water vapor and high sulfur containing fuels create sulfuric acid which precipitated sludge. Ring blow-by contained the makings for carboxylic acid. Bearing eater. Can't make acid without water, eh?

While a draft tube was a milestone in crankcase ventilation using manifold vacuum to evacuate positively was the next step in sludge reduction

Then of course there is the mess of this oiliness in an open draft system.

SquireSCA · August 19, 2019

I understand the desire to get that stuff out of there... But taking caustic materials like acid and oil and dumping it into the intake and all over the intake valves, hardly seems like a good idea... Aren't you just trading one problem, for another?

I get why the car makers don't want to, or can't vent to the air... but if I personally am not under such constraints... I mean, I live in a county in GA that doesn't even do emissions testing of vehicles... LOL

Then venting into a filter like the one I linked to, would allow excess pressure to escape, taking some of that water and oil with it.... would work, no?

Or are you saying to work properly you need the vacuum to DRAW that stuff out?

Also, if one changes their oil pretty often, would that not mitigate contaminates building up? I can't see a modern synthetic motor oil building up sludge in 4-5k miles, which most of us accumulate every few months, right?

EXSlider400 · August 19, 2019

Good points. I am just saying that with the OEM setup, oil/water is being produced and is drawn into the tube so if it is capped, what happens to the oil/water? I don’t like DI because of all this and wish the manufacturers would do a hybrid system like Toyota or just go away from DI all together. I have a 07 Silverado with 350k trouble free miles with just fluid/filter changes and grease fittings. The GM DI has been out long enough to show any issues. I have not seen anything requiring walnut blasting or anything (but that does not mean their are not).

SquireSCA · August 19, 2019

57 minutes ago, EXSlider400 said:

Good points. I am just saying that with the OEM setup, oil/water is being produced and is drawn into the tube so if it is capped, what happens to the oil/water? I don’t like DI because of all this and wish the manufacturers would do a hybrid system like Toyota or just go away from DI all together. I have a 07 Silverado with 350k trouble free miles with just fluid/filter changes and grease fittings. The GM DI has been out long enough to show any issues. I have not seen anything requiring walnut blasting or anything (but that does not mean their are not).

What I am gonna try, is not capping the vents... Those will go to those K&N vent filters and allow the water to evaporate through the filters, the oil will mostly stay in there and drip back... What I would block, is the holes in the intake tube, in my case an Airaid MIT performance intake tube. The vents would not be blocked, they would vent, but through the pod filters...

If you do regular oil changes with quality oil, you aren't gonna get sludge... and if the tradeoff is not killing your intake valves, I feel like it may be worth it.

SquireSCA · August 21, 2019

Ok, so here is what I did. Got the K&N Vent filters, and fitted them right to the click-on vent connectors. Then removed the hoses going to the intake tube, and capped the openings with rubber caps, and then safety wired them to make sure they don't loosen or go anywhere... I will drive that way for awhile, see if anything changes... I can't imagine that I would feel any difference, the question will be if there is any oil that makes it through the filters and onto the motor... So I will be checking for any drips.

My guess is that it won't do that... that the oil we see in the intake normally, is because the system is sucking on that vent tube and drawing it out... that if it was just left to it's own pressure, not much would be coming out at all.

I feel like this is merely an "emissions" thing and that there is no benefit to having it routed to the air intake, and that with GDI motors, it causes more harm.

I only have 19k miles on the truck, so I am hoping that my valves are not too gunked up... I will have them do the BG Products valve cleaning at my next oil change and I should be good to go, as no new oil is being introduced into the intake.

No $300 catch can, nothing to maintain, if this works as I hope it will...

BigBlueLB756 · August 21, 2019

This should be good...….!

SquireSCA · August 21, 2019

28 minutes ago, BigBlueLB756 said:

This should be good...….!

Meaning? Can't tell if you are being serious or sarcastic. If sarcastic, give me your ideas on why this might be a bad idea?

BigBlueLB756 · August 21, 2019

I said, "..should be..", but it's too early to have a valid opinion. You could be on to something. Or not.

Waiting for results, good or bad.

Grumpy Bear · August 21, 2019

On 8/19/2019 at 11:13 AM, SquireSCA said:

I understand the desire to get that stuff out of there... But taking caustic materials like acid and oil and dumping it into the intake and all over the intake valves, hardly seems like a good idea... Aren't you just trading one problem, for another?

I get why the car makers don't want to, or can't vent to the air... but if I personally am not under such constraints... I mean, I live in a county in GA that doesn't even do emissions testing of vehicles... LOL

Then venting into a filter like the one I linked to, would allow excess pressure to escape, taking some of that water and oil with it.... would work, no?

Or are you saying to work properly you need the vacuum to DRAW that stuff out?

Also, if one changes their oil pretty often, would that not mitigate contaminates building up? I can't see a modern synthetic motor oil building up sludge in 4-5k miles, which most of us accumulate every few months, right?

Because you have a working PCV system.

This is something you really want isn't it? Then just do it. The wheels wont fall off.

SquireSCA · August 21, 2019

LOL. Ok, I was like, "Does he know something that I don't and something is gonna blow up??"...

In theory, if there is no performance reason for this, if it is simply because the EPA doesn't want them venting the crankcase to the open air... then there should be no downside to doing this... Taking hot, oily contaminated air and injecting it into the intake manifold on a GDI motor... I can't think of any way it could possibly be a good thing, but there is absolutely at least one way for it to be a bad thing...

We shall see if this holds true. If the filters start dripping oil all over the place, then a cheap $30 catch can from Amazon to simply catch the oil and I just have to empty it occasionally, will be my next step in this...

SquireSCA · August 21, 2019

For those that know more about this stuff than I do...

My motorcycles have these systems, but they route the crankcase vent tube to the airbox, BEFORE the air filter... usually at the bottom, so while you might get a little bit collecting down there, it really has no way to get sucked up and through the air filter and into the motor...

Would that be an option? To simply get longer hoses, tap a connector into the bottom of the airbox, and get it before the filter in an area not likely to get sucked into the motor itself, while still getting some of the benefit of that vacuum to pull the crankcase vapors out?