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Do I really need Oil Catch Can (OCC) in 2012 Prius?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Prius DIY nut, Nov 7, 2023.

  1. Prius DIY nut

    Prius DIY nut Member

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    I've read in OCC thread here that 2012 Prius implemented a newer design air intake manifold.
    When I was cleaning EGR and intake recently I could still see dark oil in the intake that must be coming from PCV and sits in a paddle under the throttle body.

    Do you know if installing OCC would still be beneficial for this year Prius?

    Thanks for all useful input!
     
  2. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    It’ll help. I think the intake manifold revision was a revamp of the EGR passages (with dubious benefit); the PCV input is the same.

    An OCC will reduce oil in the intake, not eliminate it. Even the most effective ones. Two effective ones in series does better yet.

    I think even if the PCV was rerouted to atmosphere (none into intake manifold) it’ll still be a little oily: a small amount of oil seems to come from the intake ports.
     
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  3. Prius DIY nut

    Prius DIY nut Member

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    Thanks Mendel, I'll install OCC then.

    I wonder about EGR revamp you have mentioned above... My Prius has 266k km, I bought it with ~150k and I am sure no one did EGR system clean on it, but I was a bit surprised to see the EGR ports in the air intake manifold passages were all still open and had substantially less carbon than I have seen in YT videos. I wonder if that could be due to EGR cooler being more clogged... or some new design... is that what you called EGR passages revamp, do you know what did Toyota change there?
     
  4. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    I think the EGR passages went from one into four, to one into two into four.

    yeah I’d get on the full cleaning.
     
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  5. Prius DIY nut

    Prius DIY nut Member

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    When I was cleaning EGR recently, my Prius air intake seem to have had one horizontal passage from EGR pipe which then branched into each cylinder small passage. Is that what you call "one into four"? Then I must have an older design intake...?
     
  6. rjparker

    rjparker Tu Humilde Sirviente

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    It means your 2012 is not burning much oil.
     
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  7. Prius DIY nut

    Prius DIY nut Member

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    Correct, I see oil level stays approximately the same between the oil changes. That is probably why the whole EGR system was not very much contaminated. Then this all makes sense.
    I am trying to change oil (full synthetic) every 5000km or 3000mi, could that be the contributor to less EGR carbon buildup?
     
  8. rjparker

    rjparker Tu Humilde Sirviente

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    Keeping the low tension piston rings from sticking should be your goal. Frequent oil changes is about all you can do.
     
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  9. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    There might be a one-into-two intermediate. Is the EGR entrance gallery full width of the intake, or just partial. The latter I think is the revised, model year 2012, I think…
     
  10. Prius DIY nut

    Prius DIY nut Member

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    OCC is now installed. Used 7' long 3/8 fuel line and two barb splicers from PA near me. I have read the OCC big thread (in part) and being inspired by the mods there found at home a suitable plastic(HDPE) container to pack the wire mesh in it and fit it tight over the input port inside. Pocked some holes in the plastic with soldering iron so there is no air restriction. Engine works as usual, and now will monitor what comes out of it. So far there is nothing, bone dry, except gas/exhaust smell, but I only did a very short distances for a test drive and to local stores. The final OCC location is not yet decided, just to allow for quick check. PCV valve is new, so I know it's working and gases are flowing well.
     

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  11. xliderider

    xliderider Senior Member

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    I am using several overlapping layers of fine mesh stainless steel fashioned into a cone, also packed with stainless steel potscrubber material on both intake and out sides of my OCC.

    The oil condenses on the fine metal mesh and drips down. I believe it acts like the oiled gauze K&N air filters, where the oil coating the fine mesh causes more oil vapors to condense out of vapor form.

    I've mounted my OCC between the engine coolant reservoir and the engine cover, near the air conditioning lines. 20211113_084324.jpeg 20211101_105223.jpeg 20211109_112505.jpeg 20211202_114331.jpeg 20211008_165031.jpeg

    Posted via the PriusChat mobile app.
     
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  12. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    I mounted mine on a slotted angle bracket atop the lower/front cross beam. The underside of that beam is the front jacking point, so you want to put a layer of rubber between the bracket and beam, use finger-tight-and-locked fasteners, to allow that beam to flex.

    upload_2023-11-11_11-49-50.png
    (A single can would be easier, with mine the left side one is pretty close to the high voltage line (orange) into AC compressor. The cans are solidly mounted, but the engine (and attached) can be shifting a bit.)
     
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  13. Prius DIY nut

    Prius DIY nut Member

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    Thanks guys for sharing your experience and ideas. I will need to monitor how good my can setup works in a few months. Today 's temperature was only 2 Celsius and I had a longer trip to another city and back, overall around 300km with mostly high speed driving and minor slow city traffic. After returning home I opened the can to check what changed and I saw a very little, not even half of teaspoon of this stuff in the photo attached that looks like emulsion of oil and water and maybe some gasoline(?) or other light petroleum liquid floating at the top since water is heavier than oil and cannot float atop of this milky oil emulsion. Ultimate result will be by checking what eventually gets into intake manifold after some time.
    Looks like it works good so far!
     

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  14. Prius DIY nut

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    Thanks for the useful information. I got some questions about your modifications:
    1. How fine (microns) is the stainless steel mesh and where did you get it?
    2. How did you fix the smaller mesh inside the output hole?
    3. How did you fix your OCC, do you have a picture of your OCC bracket?

    Thanks again!
     
  15. Prius DIY nut

    Prius DIY nut Member

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    I like the idea of low location as it should work better with shorter hoses and better draining into OCC. I feel that I will want to check and drain the can in that low position at any moment in time and I am looking for simple way to do that. Maybe I can add a small drain with some (transparent?) hose, run it close to a service opening underneath and put some small valve at the hose end? That way I will not need to take off the underpan every time I want to check the OCC... Do you know if any one done the above?
    Therefore I am still considering the optimal OCC location.
     
    #14 Prius DIY nut, Nov 11, 2023
    Last edited: Nov 11, 2023
  16. xliderider

    xliderider Senior Member

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    This is the stainless mesh I used. I think I cut a 4 inch strip off the roll, then I cut that 4 inch strip in half to a 6 x 4 inch piece. Then I rolled it into a tube that fit snugly over the OCC inner parts. I used some wire to wrap around the mesh filter to keep it on the OCC parts.

    I crimped the other end with a hand seamer and folded it over a few times, then I folded the corners of the crimed end in slightly to clear the the walls of the OCC.

    304 Stainless Steel Woven Wire 80 Mesh 0.18mm Hole - About 11.8 X 39.4 inch Roll(30cm X100cm)- Filter Screen Sheet Filtration Cloth Fine Wire Mesh https://a.co/d/d1SHdDm

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  17. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Yeah IIRC that has been done. First off you need a bottom-draining style of OCC. My Moroso 85474 are thus, but pricey. A hose extension may be problematic over time though, if the drain or hose extension gets clogged.
    That’s basically how and when I check mine: at each DIY oil change I remove the full underpanel, do the oil change, then open the two oil catch can drains. That’s the only time I check on them. Every few years too I’ll fully remove and clean them stem-to-stern.
     
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  18. Prius DIY nut

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    I can drill and tap the hole in the can I have now. My OCC bottom is about 5-6mm think so it should be easy to modify. I need to find a suitable hardware for this.

    I want to be able to drain at any time without taking the underpanel off by having the bottom drain extended with a hose running to an opening in the underpanel for access to the coolant drain. So will be looking for drain tap, matching hose and a small valve hardware. The reason I want to closely monitor the OCC fill up because I expect that in a cold winter time there will be much more condensate amount and I do not want to risk freezing and plugging the OCC flow at any point in time, which potentially could cause some serious damage to engine seals. That is why for now I've put it in a warmer area close to EGR cooler so there is less risk of freezing in case there is happened a much of water condensate. I also have the cartridge heater in that area, so overall, since I live in a colder winter climate, I want to see how it works during the winter and finalize the location with drainage requirements next.
     
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  19. xliderider

    xliderider Senior Member

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    Here's some pictures of where my mounting bracket is attached. It is a bolt holding a bracket for the AC lines, I slipped an L-bracket under the bolt.

    Attached to the L-bracket is a short piece of aluminum L-channel that the OCC bracket slides onto, there is a hole drilled in the L-channel so I can hold the OCC bracket from shifting with a ziptie. 20211008_165122_kindlephoto-575030303.jpeg 20211008_165142.jpeg

    Posted via the PriusChat mobile app.
     
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  20. MachMarcus

    MachMarcus Junior Member

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    I think your mount (lower than the intake) is the best location to capture the most oil instead of higher than the intake. I mounted mine in the same approximate location and have a bottom drain valve. It can be drained during oil changes from underneath the vehicle. Given the low location of the PCV valve on these cars, I think routing the lines downward and mounting the catch can underneath the intake is the optimal location to capture oil that would condense at the low portion of the intake below the throttle body.
     
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  21. Prius DIY nut

    Prius DIY nut Member

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    Can you reach and drain your OCC from the service opening or you need to take off the whole underpanel to drain like Mendel described?