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Oil Catch Can, Eliminate that knock!

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by danlatu, May 22, 2017.

  1. scona

    scona Active Member

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    Yes, the gas smell is not uncommon. That is a sizeable amount of collection, but you must feel good that it is not being
    funneled back into the top of the engine. One of the benefits of having the catch can installed above is the easy access to empty it. A larger can is probably more convenient but requires more room to install and many of the larger ones are placed
    below because of that.
     
  2. jzchen

    jzchen Newbie!

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    You probably need Mendel's catch can catch can setup!

    But I noticed danlatu said this stuff is oil. What oil do you use? Maybe verify it is SN Plus from now on...

    moto g(7) power ?
     
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  3. Grit

    Grit Senior Member

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    Wow I'm serious trouble then, the oil I use is only SN w/13,000 mi OCI.
     
  4. Eddie25

    Eddie25 Active Member

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    I guess I'll have to keep an eye on it and see if it changes when the weather gets warmer.

    If it is indeed weather based condensation, I may seriously consider an uninstall. I'm not sure I can be trusted with this thing every 1500 and it feels like I'm just creating the problem that I'm trying to solve in the first place.
     
  5. Grit

    Grit Senior Member

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    My climate is not ideal for any car because I can see condensation under the top side of the brake and both coolant reservoirs when I check my oil once every 2 days, so you know condensation is mucking up inside the engine and oil when start up also. But w/the OCC, I've yet experience any start up knocks this winter.
     
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  6. Mendel Leisk

    Mendel Leisk Senior Member

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    Driving in the rain a lot?

    I would pour that into a glass jar, let it settle for a few days, see better what it is. It'll stratify, IIRC: oil at the top and water soluble goop under.

    Maybe garage parking helps too. Ours is, and I never see condensation build-up.

    FWIW, we drive maybe 3~4K kms in the 6 months between Oct and APR, and collect 100 cc at most. About 50% water based. After the summer 6 months, Apr through Oct, maybe 4~5K kms, I get about about 50 cc, mostly oil.
     
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  7. jzchen

    jzchen Newbie!

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    I know SN Plus is used in high performance engines to protect against LSPI, more specifically it's supposedly the new oil requirement for the 2.0L multi-air engine in Alfa Romeo Giulia. I connected the dots and this engine knock is likely from a similar issue. Not gonna condemn anyone for their oil choice. Just thinking of something that might help decrease the large amount the person is collecting...

    moto g(7) power ?
     
  8. jzchen

    jzchen Newbie!

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    I see condensate on the top of coolant reservoirs, on some, but not all cars, in the household. I suspect the coolant is too dilute when I see it. I don't have a refractometer to test it but if you happen to might be a good use to see your coolant health. Normally it is a sealed system unless it overheats, and even then coolant goes out from pressure, so no condensate gets in there. For the brake fluid, might need a flush with fresh fluid. I've seen it get really really dark with age, but never condensate at the top....

    moto g(7) power ?
     
  9. Eddie25

    Eddie25 Active Member

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    Yeah, lots of rain... how come you ask?

    Grit, can you explain the gas question? Does it effect catch can buildup?

    Thanks guys... lots to think about. I guess it's a waiting game now.

    What's worst case if the can ends up getting over-filled?

    I love learning about this stuff, but why does it have to be MY car.
     
  10. Grit

    Grit Senior Member

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    Changed both coolant last year, brake test strips says still good. Not nudriver here :cool:
     
  11. jzchen

    jzchen Newbie!

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    Sorry. Just saying. Didn't mean to be demeaning. Your car must live in a sauna!

    moto g(7) power ?
     
  12. Grit

    Grit Senior Member

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    Well there goes the fun.
     
  13. jzchen

    jzchen Newbie!

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    I guess my next question is, can one let this just drain out, ie while it's collecting, and not get a check engine light? I mean just look like an oil leaking Prius....

    moto g(7) power ?
     
  14. jzchen

    jzchen Newbie!

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    I'm avoiding the battery threads from now on. AND getting a Hyundai when I win the lottery. Just take it in for a new battery under warranty.

    On the oil front I know Toyota just notes ILSAC rated oils. Can't catch can me on that one!

    moto g(7) power ?
     
  15. Mendel Leisk

    Mendel Leisk Senior Member

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    I don't think so, it's a vacuum leak.

    I inadvertently did that very first install of my moroso, left drain tap open. It sounded kinda different, fixed that quick.
     
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  16. Mendel Leisk

    Mendel Leisk Senior Member

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    OTOH, you could let it drain into a secondary, sealed can, down lower. Would involve drilling/tapping for an extra spigot on the underside of first can, assuming there isn't one.
     
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  17. Pil

    Pil Junior Member

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    This seems like a quite a useful hack... added to the TO DO list!
     
  18. Mendel Leisk

    Mendel Leisk Senior Member

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    For a secondary bottle, maybe a coolant overflow tank? You'd want to ensure the hoses are tight and the cap sealing well.
     
  19. Eddie25

    Eddie25 Active Member

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    At that point, might as well just get a bigger can.

    I'm kinda stressing on mine. Took a 1000 mile all day trip this weekend and it filled up halfway. I emptied it at the hotel, luckily I just have to pull off the air box to get to it easily. The way home it filled up only a quarter, but the reality of it over-filling seems be there. I don't think it's condensation based on the quickness of it filling and seemingly having some relation to mileage. I do not know though, it has been cold and it's extremely watery.

    Does anyone else get the watery gas smelling light brown mix at anywhere close to this rate? (1 cup per 2000 miles)

    I'm really curious to hear any theories as to what's happening.

    The car runs great, but it also ran great before the catch can. My intake nor my EGR was not even that dirty and the intake was more oily, not like this stuff.

    I didn't even have a knocking problem (I did get it once, ever). It's been burning more oil as well, it's slowly crept up to about a quart every 3000 miles, but seems to have made a much quicker jump at the same time I installed the catch can. (car has 144,000 miles)

    I think I may wait till warmer weather (which seems to be now) and if it keeps doing this I will uninstall and get some data without out it.
     
  20. Mendel Leisk

    Mendel Leisk Senior Member

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    Maybe humidity and cold? And a very effective can?

    In spring, after maybe 3000 km (roughly 2K miles), mine collects 100 cc at most. About half water.

    With 2 cans in series now, it'll be interesting to see if that increases.