Catch Can Skeptic

['17 Sierra]

I agree that it would be nice to see a study on this. I'm a believer, I have an E2 on mine. The question is how much of the oil in the crankcase vapors is actually caught with a catch can. It might look like a lot but that question has never been answered. That milky substance that many seem to think is REALLY bad for the motor, isn't. That is just condensation that's mixed with the oil that hasn't been heated enough to evaporate yet. Moisture won't hurt anything once it's in the combustion chamber and once the oil heats up enough, the condensation just evaporates, burns in the CC and goes down the line and out the pipe.

[15 Z71]

I say just drive it. Lots of people with these 14 and newer trucks with no problems and no cans. I work with a couple of people that have over a 100,000 and 0 issues. Dont think it matters either way.

[CSI-WALLEYE]

2 hours ago, '17 Sierra said:

I agree that it would be nice to see a study on this. I'm a believer, I have an E2 on mine. The question is how much of the oil in the crankcase vapors is actually caught with a catch can. It might look like a lot but that question has never been answered. That milky substance that many seem to think is REALLY bad for the motor, isn't. That is just condensation that's mixed with the oil that hasn't been heated enough to evaporate yet. Moisture won't hurt anything once it's in the combustion chamber and once the oil heats up enough, the condensation just evaporates, burns in the CC and goes down the line and out the pipe.

This is an example of how the fact oil is found in a can could be misinterpreted.  If the can preferentially removed water as compared to oil, then the can could make deposits worse.  Because theoretically, the water could soften deposits and if the can removed the water it could actually concentrate the oil being delivered to the valves.  I don't think this is happening but the fact is that you don't know unless you perform the experiment.

[M-Wheeler]

Best way to see if a catch can really works is to install 2 of them. Have one dump to the other. If the 2nd one is collecting anything, then you know the first can is not working like it should....

 

Anyhow, with that being said, I empty mine every 1,000miles and have about an ounce of crap each time.

 

Also, PRIOR to every oil change (5K) I do the DI/Turbo intake clean. I made a special fitting on CAI after my MAF, spray in 1-2 second bursts at 2000rpm, let soak for an hour, run it down freeway for 10-20 miles. dump oil/filter, rinse repeat. 

 

35K, runs like a top!

[Jacoby]

2 hours ago, M-Wheeler said:

Best way to see if a catch can really works is to install 2 of them. Have one dump to the other. If the 2nd one is collecting anything, then you know the first can is not working like it should....

 

Anyhow, with that being said, I empty mine every 1,000miles and have about an ounce of crap each time.

 

Also, PRIOR to every oil change (5K) I do the DI/Turbo intake clean. I made a special fitting on CAI after my MAF, spray in 1-2 second bursts at 2000rpm, let soak for an hour, run it down freeway for 10-20 miles. dump oil/filter, rinse repeat. 

 

35K, runs like a top!

Let me see this fitting you made. That’s a great idea. 

 

Ive done the cleaning once so far and just sprayed it in the pcv inlet on the side of the intake

[Gagliano7]

I think the best thing to do is clean the valves once a year with the CRC spray or sea foam. I have seen videos where this works. I think the catch can is a waste of money but i know on here i am in the minority.  Think about how many gm trucks and suv's with these motors don't have a catch can. Probably 99% of them on the road which is millions.

Edited March 29, 2019 by Gagliano7

[Jacoby]

5 minutes ago, Gagliano7 said:

I think the best thing to do is clean the valves once a year with the CRC spray or sea foam. I have seen videos where this works. I think the catch can is a waste of money but i know on here i am in the minority.  Think about how many gm trucks and suv's with these motors don't have a catch can. Probably 99% of them on the road which is millions.

When u can get one on eBay for $50 bucks I’d hardly say it’s a waste of money. That’s cheap insurance

[TRKLGND]

49 minutes ago, Jacoby said:

When u can get one on eBay for $50 bucks I’d hardly say it’s a waste of money. That’s cheap insurance

The $50 ebay cans are not the one the guys here are installing.  Most of what I see recommended start at around $200.

[diyer2]

It can't hurt  anything so I see no reason not to have one.

I put one on my 2012 that does not have GDI.

Cheaper than an insurance payment probably.

 

[Jacoby]

39 minutes ago, paracutin said:

The $50 ebay cans are not the one the guys here are installing.  Most of what I see recommended start at around $200.

I agree. My point was that there are cheap cans out there that provide the same function as the more expensive ones. Therefore it being so cheap doesn’t mean it’s a waste of money. 

[TRKLGND]

Just now, Jacoby said:

I agree. My point was that there are cheap cans out there that provide the same function as the more expensive ones. Therefore it being so cheap doesn’t mean it’s a waste of money. 

They absolutely do not!  Most of the $50 ebay cans are simply an empty can.  No baffling, no screens, nothing to keep whatever comes in from going right back out.  
Disclaimer: I do not use a catch can so I have no dog in this fight but I have see the results from many test, unscientific as they may be, that show the cheap cans collect almost nothing compared to the $200+ cans.
Since you seem to think that $50 is cheap and not a waste of money I have a case of empty beer cans (catch cans) you can buy.  Only $10 each.  Quite a deal! 

[CSI-WALLEYE]

53 minutes ago, paracutin said:

They absolutely do not!  Most of the $50 ebay cans are simply an empty can.  No baffling, no screens, nothing to keep whatever comes in from going right back out.  
Disclaimer: I do not use a catch can so I have no dog in this fight but I have see the results from many test, unscientific as they may be, that show the cheap cans collect almost nothing compared to the $200+ cans.
Since you seem to think that $50 is cheap and not a waste of money I have a case of empty beer cans (catch cans) you can buy.  Only $10 each.  Quite a deal! 

Just out of curiosity, you seem to be knowledgeable about the cans but do not use one.  Would you be willing to share your reasoning? 

[TRKLGND]

8 minutes ago, CSI-WALLEYE said:

Just out of curiosity, you seem to be knowledgeable about the cans but do not use one.  Would you be willing to share your reasoning? 

Absolutely.
1st: As you pointed out in your OP, there is no proof they actually lessen intake valve deposits.  

2nd: It gets pretty cold in the winter where I live.  I have seen several instances where folks report mail seal failure due to over-pressurization.  The dealer and or mechanics attributed this to the catch can freezing.  This brings me to number 3.

3rd: Depending on your dealer, this type of modification can cause them to deny warranty coverage for most anything engine related.  Someone is going to quote the Mag-Moss Warranty Act and that the dealer or GM has to prove that your mod caused the issue they are refusing to warranty.  This is all true.  However, depending on the issue, I may not have the funds to pay for the repairs out of pocket while fighting with GM over the warranty.  I also own only one vehicle so I can't afford to be without mine for an extended period.   I'm not a gambler by nature and certainly not with a $50k truck.

There are other reasons but we'll start with those.

[Jacoby]

1 hour ago, paracutin said:

They absolutely do not!  Most of the $50 ebay cans are simply an empty can.  No baffling, no screens, nothing to keep whatever comes in from going right back out.  
Disclaimer: I do not use a catch can so I have no dog in this fight but I have see the results from many test, unscientific as they may be, that show the cheap cans collect almost nothing compared to the $200+ cans.
Since you seem to think that $50 is cheap and not a waste of money I have a case of empty beer cans (catch cans) you can buy.  Only $10 each.  Quite a deal! 

Dude back in the day all the cans were empty.  All guys did was fill it with a steel scouring pad to use as a filter.  Open up a $200 catch can and they use the same thing.  Youre just paying extra for them to include it in their design.  These engines don't produce enough vacuum to suck up fluid from the bottom of the can.  Theres tons of folks using cheap cans and collecting just as much fluid as the more expensive ones.  Im not advocating someone buying a cheaper can Im just saying that the design is simple.  Crankcase fumes go in one side and out the other.  Its as simple as that.  And don't make me out to be some **** by saying $50 isn't a lot of money.  That's not what I said.  But $50 is way less than $200.  That's just basic math

[15 Z71]

Ahhhh, I love the catch can debates. Lol