Oil catch can

I'm very surprised to see folks using these with the additional care they require on "basic" street-driven vehicles.
I had some interesting discussions with a well-respected member, who for now, will remain anonymous. We had a long discussion about catch cans and their usefulness. I’ll try to summarize:

All engines make oil mist, some more than others. It is perceived by several experts that this is present in nearly all engines, but more of an issue on some designs. There’s no real way to know which design is more prone other than experience. PCV design and placement also plays a role.

However, in the types that do collect this oil mist in the PCV system, the trappings can actually tell you about the composition of your oil, and this is a current test I’m running on my 3.5 EB (about 2 ounces total collected so far). When the oil is analyzed, if the additive concentrations appear much higher than the UOA of the oil, this tells you that the base oil is evaporating rapidly and that the mist is therefore more concentrated with the “heavier” additives. If the composition is roughly the same as the VOA, this tells you all the oil in the PCV system is due directly to the mist, since it is collecting the lighter base oil and the heavier additives at the same rate.

Obviously in winter there will be some condensate collected, but my source did not feel that fuel will be a considerable amount, simply because they’re too light to condense even in the PCV system, or at least after the system has been warmed during operation.

And, for those who think “lots” of condensation happens because the can is aluminum, at least on my truck I only made the mistake once of trying to check the catch can directly after a drive- it made my hand pink and felt like I had touched a hot pan; I’d bet it was every bit of 160*F or more. Remember, the air passing through the PCV is heated by the block at ~210* and the oil at nearly the same, so after a long enough time, any temperature delta will be nil. That means probably 200*+ during Highway operation especially in summer.

Will let everyone see results when I get the catch can UOA results.
 
Here's a good catch can video with UOA by Charles "The Humble Mechanic" - a very solid YouTuber (VW/Audi).

 
I've seen plenty of evidence. Take my fa20dit for example. It would cake the valves in 20k miles regardless of oil, fuel, driving conditions. The s4, had to clean the valves on a 40k mile engine. Mini turbo, those things were so caked, it would cause misfires. Mk7 golf r. Same thing.

Can't judge every occasion by your car or driving style. While I agree Italian tune up helps, many cars do not see the use yours does. I bet your car spends more time on the opposite side of vacuum than it does in it.
My experience lies in the MQB/EA888 gen 3 engines for VAG - I just don't read much about valve deposits on these cars and spend a ton of time on the forums/FB groups vs. prior gens which has been attributed to the PCV system design. Driving a car hard sometimes and pulling high RPM is always (to me) a good thing for any DI vehicle but many folks are scared of doing it when this is well within their capabilities/limits. Here's a good MK7 R video:

 
I had some interesting discussions with a well-respected member, who for now, will remain anonymous. We had a long discussion about catch cans and their usefulness. I’ll try to summarize:

All engines make oil mist, some more than others. It is perceived by several experts that this is present in nearly all engines, but more of an issue on some designs. There’s no real way to know which design is more prone other than experience. PCV design and placement also plays a role.

However, in the types that do collect this oil mist in the PCV system, the trappings can actually tell you about the composition of your oil, and this is a current test I’m running on my 3.5 EB (about 2 ounces total collected so far). When the oil is analyzed, if the additive concentrations appear much higher than the UOA of the oil, this tells you that the base oil is evaporating rapidly and that the mist is therefore more concentrated with the “heavier” additives. If the composition is roughly the same as the VOA, this tells you all the oil in the PCV system is due directly to the mist, since it is collecting the lighter base oil and the heavier additives at the same rate.

Obviously in winter there will be some condensate collected, but my source did not feel that fuel will be a considerable amount, simply because they’re too light to condense even in the PCV system, or at least after the system has been warmed during operation.

And, for those who think “lots” of condensation happens because the can is aluminum, at least on my truck I only made the mistake once of trying to check the catch can directly after a drive- it made my hand pink and felt like I had touched a hot pan; I’d bet it was every bit of 160*F or more. Remember, the air passing through the PCV is heated by the block at ~210* and the oil at nearly the same, so after a long enough time, any temperature delta will be nil. That means probably 200*+ during Highway operation especially in summer.

Will let everyone see results when I get the catch can UOA results.
I recently changed out my PCV for a more stout revision - the EA888 gen 3 engines have a good PCV system which I attribute to the fact that you don't read a lot of about intake valve deposit issues on these cars. The real question in this discussion to me is...ok so we always have some oily/fuelly mist going back through the PCV some of which will reach the intake but...so what? As long as the deposits are minimal this really doesn't have much of an impact. Cold start misfires are definately one of the issues you can get from egregious build up so unless you are having an issue, send it.
 
I recently changed out my PCV for a more stout revision - the EA888 gen 3 engines have a good PCV system which I attribute to the fact that you don't read a lot of about intake valve deposit issues on these cars. The real question in this discussion to me is...ok so we always have some oily/fuelly mist going back through the PCV some of which will reach the intake but...so what? As long as the deposits are minimal this really doesn't have much of an impact. Cold start misfires are definately one of the issues you can get from egregious build up so unless you are having an issue, send it.
You know it. (y)
Here's a good catch can video with UOA by Charles "The Humble Mechanic" - a very solid YouTuber (VW/Audi).


thanks for posting that , I will check it out later. I like checking out stuff like that.
 
From 2007 to 2015 GM sold vehicles with an inferior pvc system built into the driver side valve cover. GM issued TSB 10-06-01-008M (final version) to address oil consumption issues. Part of this TSB is to install an updated driver side valve cover with improved built in pvc system. Because of the poor pvc design oil gets sucked out of the valve cover, into the induction system, and into the combustion chamber. This causes piston ring sticking, etc, resulting in oil consumption.

In late 2018, shortly after purchasing our used 2007 GMC Yukon Denali w/6.2L, I realized it was burning a lot of oil. I joined a forum for the vehicle and members recommended that I install an oil catch can inline between the valve cover and the intake manifold. I did, a $25 chicom amazon unit. To improve it, I installed my own fittings, ball valve to drain it, and stainless pot scrubber material to help drop out liquid. Total CC cost = $35. I installed it and it was catching 1 oz of oil every 1000 miles, no water. It has been working flawlessly for 4 yrs and 44k miles. Its never has caught any water. It catches 2 oz of a dark oil and gasoline liquid every 8k miles.

The improved valve cover and the piston/combustion chamber soak I did w/Gunk brand Motor Medic cured the consumption problem. The vehicle nolonger needs the CC. I left it in place. It requires no mx between oil changes.
Catch can oil.jpg

Catch can 1.jpg

Catch can 2.JPG

Catch can.JPG
 
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