1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Oil Catch Can (aka Air-Oil Separator)?

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by Mendel Leisk, Oct 22, 2017.

  1. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,463
    38,101
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Anyone done this on a 4th gen, or thinking about it? Strategies?

    No time like the present.
     
    RMB and mjoo like this.
  2. xliderider

    xliderider Senior Member

    Joined:
    Apr 19, 2012
    7,842
    3,099
    0
    Location:
    Honolulu, HI
    Vehicle:
    2011 Prius
    Model:
    Three
    You should provide a link to the Gen 3 thread, so the Gen 4 ppl will know what the concern is all about. ;)

    Posted via the PriusChat mobile app.
     
    Mendel Leisk likes this.
  3. Prodigyplace

    Prodigyplace Senior Member

    Joined:
    Nov 1, 2016
    11,696
    11,317
    0
    Location:
    Central Virginia
    Vehicle:
    2017 Prius
    Model:
    Two
    I have only had mine a year and less than 12K miles. I know about them but figure I can wait a while longer. :D
     
    RCO likes this.
  4. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,463
    38,101
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Good point. I guess @danlatu 's thread is the main one:

    Oil Catch Can, Eliminate that knock! | PriusChat

    The main culprit seems to be airborne oil mist from the PCV valve, condensing/pooling in the intake manifold, and maybe getting sucked into the combustion chambers as well. This is something that's happening from the get go, maybe you can't be too soon? I've heard more that one comment about adding this right away, with a new vehicle.
     
    j12piprius likes this.
  5. Prodigyplace

    Prodigyplace Senior Member

    Joined:
    Nov 1, 2016
    11,696
    11,317
    0
    Location:
    Central Virginia
    Vehicle:
    2017 Prius
    Model:
    Two
    You are assuming they made no changes for Gen 4. We know they increased the fuel efficiency of the engine. I believe somebody had suggested that a design change could have alleviated the issue,
     
    RCO likes this.
  6. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,463
    38,101
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Maybe you're thinking of the EGR improvements? Not sure. A relocation of the PCV valve, positioning higher up on the crankcase wall might help, or a better baffle system leading to the PCV valve connection. Not sure.

    If you can get a look down the throat of the throttle body and see oil beyond, that would be a tip off to the need for an OCC.
     
    RCO and mjoo like this.
  7. Prodigyplace

    Prodigyplace Senior Member

    Joined:
    Nov 1, 2016
    11,696
    11,317
    0
    Location:
    Central Virginia
    Vehicle:
    2017 Prius
    Model:
    Two
    How easy is that to get to? I assume it is under the plastic top cover?
    I just have not worked much on a Prius.
     
  8. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,463
    38,101
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Removal of intake manifold is likely the best approach. There's (as far as I know) a couple of hoses, if it's similar to 3rd gen.

    One hose (the one you're maybe thinking of) goes from the valve cover to a spigot on the intake air snorkel, at a point between the air filter and the throttle body.

    The other hose, and this is the trouble maker, runs between the Positive Crankcase Ventilation (PCV) valve (mounted high on the crankcase wall, below intake manifold), to a spigot on the side of the intake manifold, downstream from the throttle body.

    An OCC is typically installed along that second hose.
     
    Prodigyplace likes this.
  9. Prodigyplace

    Prodigyplace Senior Member

    Joined:
    Nov 1, 2016
    11,696
    11,317
    0
    Location:
    Central Virginia
    Vehicle:
    2017 Prius
    Model:
    Two
    Pictures? I guess I am more visual.
    On my Tundra, the intake manifold is pointed out the front of the engine. I would just need to remove the air cleaner hose to inspect.
     
    #9 Prodigyplace, Oct 23, 2017
    Last edited: Oct 23, 2017
  10. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,463
    38,101
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Here's the hose between PCV valve and intake manifold on 3rd gen. Throttle body is mounting on Intake Manifold just to the left of left end of hose, PCV valve is screwed into crankcase on right end.

    upload_2017-10-23_10-0-39.png

    I ended up cutting that hose at the mid-point, rotating the two resultant "elbows" downward, and splicing in the oil catch can.

    Best I can do btw, haven't got a 4. You might be able to see the PCV plumbing, by just removing the air intake snorkel and air filter box: the intake manifold looks very compact and high up.
     
    #10 Mendel Leisk, Oct 23, 2017
    Last edited: Oct 23, 2017
    Prodigyplace likes this.
  11. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,463
    38,101
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    This might be the hose on the 4th gen:

    upload_2017-10-23_10-27-42.png

    If not, it's likely in that mass of spaghetti, somewhere.
     
    #11 Mendel Leisk, Oct 23, 2017
    Last edited: Oct 23, 2017
    mjoo, RCO and Prodigyplace like this.
  12. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,463
    38,101
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
  13. RMB

    RMB Senior Member

    Joined:
    Jun 21, 2016
    406
    642
    0
    Location:
    Oakland, CA
    Vehicle:
    2014 Prius
    Model:
    Three
    Oh well, this OCC topic isn't very popular with Gen 4 members. Either Gen 4's are still new to cause any concerns and/or the improved systems won't cost problems?
     
    RCO, Raytheeagle and Mendel Leisk like this.
  14. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,463
    38,101
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    A bunch of procrastinating grasshoppers, lolling in the summer meadow... :rolleyes:

    Pot calling the kettle black: it took me to 70K kms to wake up, but eight-o'clock-day-one is the optimum time to address this.
     
    Raytheeagle, RMB and mjoo like this.
  15. Raytheeagle

    Raytheeagle Senior Member

    Joined:
    Jul 1, 2016
    11,251
    15,474
    0
    Location:
    Bay Area, California
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    How much oil have you caught with your new setup?
     
  16. RMB

    RMB Senior Member

    Joined:
    Jun 21, 2016
    406
    642
    0
    Location:
    Oakland, CA
    Vehicle:
    2014 Prius
    Model:
    Three
    I will check on it this coming Saturday, exactly one week after installing my OCC. I didn't drive my Prius Sunday and Tuesday, so probably wasn't enough driving to warrant a measurement, but after a week I will have better picture of how much oil go through the PCV and into the intake manifold.
     
    Raytheeagle likes this.
  17. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,463
    38,101
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    I got a scant tablespoon, if that, in the first 350 kms or so. My setup is pretty much only accessible from below, so it'll be spring oil change when I'll open the drain tap again, measure what comes out. I've got a wee jar that I've engraved with CC lines, will see what I get with 4~5K kms.

    More telling, pull the throttle body again (or at least have a look through the throat), and see if it's stayed oil-free. I suspect besides the PCV, a slight amount is trickling down from the intake ports.
     
    RMB likes this.
  18. RMB

    RMB Senior Member

    Joined:
    Jun 21, 2016
    406
    642
    0
    Location:
    Oakland, CA
    Vehicle:
    2014 Prius
    Model:
    Three
    IMG_3617.JPG
    177 miles since installing oil catch can, exactly one week ago. Normal routine driving except for the very same day going home after the meetup where there was a full throttle uphill section on Hwy24, HSD indicator way up in the Power section. Probably blew more oil into the catch can than my normal route would do. From the picture I took, what do you estimate of the collected amount? I think maybe about 5 ml? That estimate is comparing to my baby boy's formula bottle LOL.

    When I installed the catch can, I didn't pull out the intake manifold for a thorough cleaning, but I did see a puddle of oil underneath the throttle body. But then, both sides of the throttle plate was very clean. Today I didn't have time to pull out the air intake box and snorkels to look at the throttle body for comparison, I doubt there will be any difference since there was oil in the manifold before adding the catch can.
     
    RCO, Mendel Leisk and Raytheeagle like this.
  19. Raytheeagle

    Raytheeagle Senior Member

    Joined:
    Jul 1, 2016
    11,251
    15,474
    0
    Location:
    Bay Area, California
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    The Oakland Hills around the Caldecott tunnel are pretty steep:(.

    When I was going to the Children’s hospital in Oakland a couple of weeks back, I could see the effect on mpg.

    I’m just glad I don’t have that commute everyday:whistle:.

    There are better ways to spend 2.5 hours in a morning (y).
     
    RMB and RCO like this.
  20. Prodigyplace

    Prodigyplace Senior Member

    Joined:
    Nov 1, 2016
    11,696
    11,317
    0
    Location:
    Central Virginia
    Vehicle:
    2017 Prius
    Model:
    Two
    RCO likes this.