Point of oil catch can?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by kehyler, May 1, 2019.

  1. Raytheeagle

    Raytheeagle Senior Member

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    Is Blah in a CARB state:whistle:?
     
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  2. Mendel Leisk

    Mendel Leisk Senior Member

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    Aren't there some cars that come stock with an oil catch can, maybe with another name, but the same principle? For what it's worth, the label on my Moroso:

    upload_2019-5-4_7-16-29.png
     
  3. Rebound

    Rebound Senior Member

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    Under CARB rules, you may not modify a car’s emission equipment, period. Of course this is a beneficial mod, but if the visual inspection finds it, the car won’t pass smog
     
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  4. Rebound

    Rebound Senior Member

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    It’s a mist, but it’s still liquid motor oil, the same stuff that coats the engine at those same high temperatures. It’s a common design for an engine or valve cover to have a baffle before the PCV valve, and it’s common for the PCV to be high on the engine, to keep oil out. But it’s low on the Prius engine, practically in the oil sump.

    Oil isn’t supposed to enter an engine’s intake manifold, and it isn’t supposed to be burned inside the cylinders.
     
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  5. Mendel Leisk

    Mendel Leisk Senior Member

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    Through winter: motor oil, plus water, plus maybe some gas. There's a definite dividing line: darker oil above, and this cream colored gunk below.

    In summer, mostly motor oil though, and lot less volume.
     
  6. wheezyglider

    wheezyglider Active Member

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    There don't appear to be any for the Prius (or any other gas car after 1993). According to this CARB page regarding Aftermarket, Performance and Add-On Parts:
    However searching their database of Executive Orders approving parts in the "Blowby Oil Separator" device category, there aren't any approved for recent cars.

    What's not clear is whether add-on manufacturers have even applied for and been denied approval in recent years, and if so why. Seems like there would be a big market for a CARB-legal catch can for the 3rd gen Prius.
     
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  7. CR94

    CR94 Senior Member

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    Curiously, despite all that, my car's oil consumption is very low, so far.
     
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    I get a couple of ounces of oil in the OCC at most, between oil changes. Fall oil change that's pretty much all I get. Spring, there's an extra 3~4 ounces of water gunk.
     
  9. Rebound

    Rebound Senior Member

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    That’s true, but the problem causes these cars to lose roughly 100ml between every oil change, so in the course of 50,000 miles, you’ve poured a quart of motor oil into the car’s intake system, and a portion of that is clogging up the exhaust gas recirculation.
     
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  10. Mendel Leisk

    Mendel Leisk Senior Member

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    Might be worth noting, I'm following the Canadian 3rd gen schedule for oil/filter changes, 6 months or 8K kms, whichever comes first. Months are coming first (to put it mildly), only doing about 3K kms between oil changes, and oil catch can drainings.
     
  11. spiralhelix

    spiralhelix Active Member

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    So really looking at the engine/oil issue with the PCV and adding a catch can, I was mistaken in my memory as to where the PCV tube mated to the Intake manifold. It is much lower that I was originally thinking so I can see how it can be dispersed amongst all the intake ports and any left over pooling down at the throttle body, but the catch can is only installed between these two points. Any other vacuum lines don't play a role in the use of an OCC. I feel like I understand how this oil mist makes it's way to the EGR clogging it. What I'm failing to grasp then, based on the statements above, if fresh air is not burning hotter in the chamber and the outcome is only higher HP but worse emissions(?), why do we care if the EGR gets clogged??? How are Headgaskets giving up the ghost mostly at the first cylinder due to the EGR being clogged? Don't head gaskets blow due to excess friction from the expansion and contraction of the metal parts it separates or from excessive heat buildup causing it to warp?

    So what am I missing or ignorantly thinking: HP is a measure of power output. Power is generated by the combustion of gases adding to the already momentum of the piston head moving down. To get more "power" the explosion has to be greater. to get a greater explosion either more fuel has to burn or more oxygen has to be added or both. Combustion is bonds breaking and new molecules forming with a release of energy as heat (25 O2 + 2 C8H18 → 16 CO2 + 18 H2O + energy). ^fuel + ^O2 = ^Power and Power=release of energy, therefore ^fuel +^O2=^Energy Release. I don't see how coolant regulates the chamber temperature. The coolant regulates the block temperature by being a heat sink. If the block gets hotter, the coolant moves faster to pull heat away. The thermostat regulates how much coolant circulates, the radiator dumps the heat the coolant absorbs. Engines do run better at certain temps which is why a thermostat will open and close. To tie it into the EGR, and I ran the interstate with the computer attached, at 80 mph the ERG was showing 50-60%. Since the exhaust gases contain less O2 than fresh air, less fuel is needed for the proper fuel/air stoiciometric ratio of 14.7:1.

    I certainly am not trying to be argumentative, I'm just really interested in how a clogged EGR seems to be blowing head gaskets if temperature is not a factor. I also don't want to be misunderstood thinking I'm misguided in wide temperature differences. The difference can be less than 1ºF and still cause problems.
     
  12. Mendel Leisk

    Mendel Leisk Senior Member

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    I'm completely unsure of the science, but the one thing I'm clinging to, is that the gas introduced by a properly functioning EGR is lowering combustion chamber temperatures. How and why, maybe @mjoo can explain?
     
    #32 Mendel Leisk, May 6, 2019
    Last edited: May 6, 2019
  13. Rebound

    Rebound Senior Member

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    An EGR reduces formation of Nitrous Oxides by diverting some of the exhaust gas back into the intake manifold. The exhaust gas is non-combustible, and this therefore reduces combustion temperature, which reduces NOx formation. That’s the principle of an EGR. At idle, the valve needs to be closed or else the engine will stall. When fully hot, if the EGR is clogged, combustion temps can exceed the engine’s design spec.

    So if the EGR clogs, you get higher combustion temps. If oil gets into the EGR, it gets pretty nefarious: First, the EGR cooler loses efficiency. Second, oil enters the intake manifold and cylinders. Third, the oil clogs the intake manifold passages arbitrarily, so you have different temps on different cylinders, which is a bad imbalance. You mention that there are thermostats but they don’t monitor individual cylinders.

    I don’t know what causes the actual failure. It could be the higher heat, it could be engine knock caused by burning oil, it could be one cylinder getting much hotter or detonating differently than the others. I think an expert would need to tear apart a failed engine and analyze the gasket and the residues to be certain.
     
    #33 Rebound, May 6, 2019
    Last edited: May 6, 2019
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  14. Mendel Leisk

    Mendel Leisk Senior Member

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    And the PCV "pitches in" with that.
     
  15. spiralhelix

    spiralhelix Active Member

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    ok, so i have to admit i've been pretty confused with some of @Rebound's responses. If we go back to what originally started this discussion path:

    After re-reading some of the posts, For me I think some things got lost in translation. I kept reading that @Rebound's original response to @kehyler's question was pointed at the engine temp comment, but was it really just pointing out that the HP demand would not be the same with those conditions?

    i think we all agree the bad engine design and how it leads to a clogged EGR cooler. so can we stick a pin in the clogging part of the equation?

    The jury is still out on exactly how it leads to head gasket issues, but the two definitely appear to be connected. The working theory is that more oxygen from fresh air has higher combustion temps (whether it is in one or more chambers) which then affects the head gasket in a couple possible ways. yes/no?

    I'm very much interested in other theories as to why blown head gaskets seem to be tied into EGR if temperature is NOT a factor. I'm not excited to hear, "it's a high mileage car, what do you expect. Head gaskets wear out". I get that they can fail for other reasons. Why i think the EGR is tied to this particular thing is that the symptoms start with rough starts/shuddering, toyota is replacing some of these parts, but if left long enough without doing any of the things mentioned countless times, it sure seems like a guarantee you will blow a head gasket. I know for my story, it was a little over a week from first symptom to requiring an engine swap. And the coolant was fine two days before we eventually took it to the dealer.
     
  16. wheezyglider

    wheezyglider Active Member

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    No Grand Unified Theory of everything here, but just playing along. You can see from this photo of the intake manifold that when the flow from the EGR pipe is low (entering from left in photo), the output favors the opposite cylinder. (The one next to the timing chain, that's #1 yes?)
    EGR low flow favors cylinder 1.JPG

    That exhaust gas is 500F and hasn't been cooled because the EGR cooler fins are insulated with carbon. So its hot and uneven. We get expanding the head near cylinder #1, and voila, HG failure at the nearest weak point. Maybe.
     
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  17. Grit

    Grit Senior Member

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    Are you an undercover Bill Norton?!
     
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  18. spiralhelix

    spiralhelix Active Member

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    yes, cylinder #1 is on the passenger side of the car (next to the timing chain). I should take a closer look at my intake. I just remember it being dirty all around. Here is my engine with the block reading left to right 1-->4, and the head in reverse left to right 4-->1. In my case cylinder 1 was the problem. i'm curious though why the intake valves look like they have dried coolant. I get why #1 looks clean.
    IMG_2801.jpg IMG_2807.jpg
     
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  19. spiralhelix

    spiralhelix Active Member

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    oh, and sorry, I don't know who bill norton is and google didn't seem very helpful for me to understand the reference. An NFL player or a writer for Buffy. You sayin' i type too much??? hahaha.
     
  20. Mendel Leisk

    Mendel Leisk Senior Member

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    Bill Norton was/is a member, who's not convinced the EGR system needs cleaning.
     
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