Faint Oil Smell in Cabin

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Rebound, Oct 24, 2021.

  1. Rebound

    Rebound Senior Member

    Joined:
    Mar 11, 2010
    3,917
    2,525
    0
    Location:
    Portland, OR
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    Edit: Looks like I figured it out. The crankcase was overfilled. The dipstick in a Prius can be notoriously difficult to read.

    Finally installed an OCC two months ago, and I now notice a faint oil smell in the cabin. I pulled the belly pan and air intake and saw no signs of oil leakage. Emptied about 1” of brown goop out of the catch can, and I tightened the oil sump bolts, where there’s a tiny bit of oil seepage. They turned about 1/4 turn, so that may help but doesn’t explain an oil smell. Mileage remains the same, car runs great. Cabin filter was replaced back in July.

    Only possibility I can think of is that I spilled a little oil during the catch can install, and it’s slowly burning off.

    All around valve cover, it’s dry, as far as I can see. No signs of oil anywhere, except the usually grittiness on the bottom of the engine.

    Any suggestions?
     
    #1 Rebound, Oct 24, 2021
    Last edited: Oct 24, 2021
  2. tankyuong

    tankyuong Senior Member

    Joined:
    Nov 9, 2012
    1,399
    608
    0
    Location:
    Central MO
    Vehicle:
    2012 Prius c
    Model:
    II
    Keep vent on recirc
     
  3. rjparker

    rjparker Senior Member

    Joined:
    Jun 6, 2008
    4,187
    2,231
    2
    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    Usual leak is at the timing chain cover but I would bet its the OCC venting or the wrong hoses connecting it.
     
  4. Mendel Leisk

    Mendel Leisk Sand Pounder

    Joined:
    Oct 17, 2010
    45,945
    32,812
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    I know this is kinda stupid, but just to rule it out, check the oil fill cap?

    Don't ask...
     
    Raytheeagle, fuzzy1 and Rebound like this.
  5. rjparker

    rjparker Senior Member

    Joined:
    Jun 6, 2008
    4,187
    2,231
    2
    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    How much was the crankcase overfilled?
     
  6. Rebound

    Rebound Senior Member

    Joined:
    Mar 11, 2010
    3,917
    2,525
    0
    Location:
    Portland, OR
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    I still can’t tell. I drove it about ten miles to warm it up, took a bunch of added measurements, and I’m still not sure if it’s overfilled or not. I hate the dipstick design on this car.
     
  7. Mendel Leisk

    Mendel Leisk Sand Pounder

    Joined:
    Oct 17, 2010
    45,945
    32,812
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Pull the dipstick, wait 5 minutes (say check tire pressures) then do the check. When you pull the dipstick it draws oil up the tube; the delay gives it time to drain back down.

    also, check both sides; I find the side towards the front more definitive.

    FWIW, my refill technique: drain well, button everything up, add 4.2 liters (4.5 qts), and don’t even bother checking dipstick for a few days.
     

    Attached Files:

    burebista likes this.
  8. rjparker

    rjparker Senior Member

    Joined:
    Jun 6, 2008
    4,187
    2,231
    2
    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    Sometimes you can carefully place the dipstick flat on a paper towel to transfer the level to the paper. I find checking it in the morning before starting is often easier since the oil has drained back on the dipstick. Just pull and check.

    It has been reported that overfilling will push more oil through the pcv to the intake but normally you would not smell oil. So a vapor leak in the aftermarket OCC, the hoses used are permeable or there is oil leaking (maybe leaked) on the engine.
     
    burebista likes this.
  9. burebista

    burebista Member

    Joined:
    Sep 3, 2019
    97
    75
    0
    Location:
    Romania
    Vehicle:
    2010 Prius
    Model:
    N/A
    I don't bother to add 4.2l. Just a 4l bottle and I'm at 75% on dipstick. Good enough for me.:)

    Yep, this is what I'm doing. (y)
     
    Mendel Leisk likes this.
  10. Mendel Leisk

    Mendel Leisk Sand Pounder

    Joined:
    Oct 17, 2010
    45,945
    32,812
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Also, if you use reading glasses, this is definitely a time for them.
     
  11. Rebound

    Rebound Senior Member

    Joined:
    Mar 11, 2010
    3,917
    2,525
    0
    Location:
    Portland, OR
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    Two sides of the same dipstick. How am I supposed to figure out if there’s too much oil?

    IMG_5690.jpg
    IMG_5689.jpg
     
  12. rjparker

    rjparker Senior Member

    Joined:
    Jun 6, 2008
    4,187
    2,231
    2
    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    The side that curves down and shows the least
     
  13. Mendel Leisk

    Mendel Leisk Sand Pounder

    Joined:
    Oct 17, 2010
    45,945
    32,812
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Do you know how much you put in?
     
  14. Georgina Rudkus

    Georgina Rudkus Senior Member

    Joined:
    Sep 15, 2018
    2,062
    1,472
    0
    Location:
    Taylors, SC
    Vehicle:
    2012 Prius v wagon
    Model:
    Two
    Which oil catch can did you use, Rebound?

    The one that I used did not come with an o-ring seal on the integral dip stick. The dipstick was threaded M6x1.0.

    I added an o-ring to the dipstick in the can before installing it.
     
  15. Rebound

    Rebound Senior Member

    Joined:
    Mar 11, 2010
    3,917
    2,525
    0
    Location:
    Portland, OR
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    I don’t remember the brand. It has a dipstick, and it’s screwed in firmly, but I don’t recall checking for an o-ring.
     
  16. Georgina Rudkus

    Georgina Rudkus Senior Member

    Joined:
    Sep 15, 2018
    2,062
    1,472
    0
    Location:
    Taylors, SC
    Vehicle:
    2012 Prius v wagon
    Model:
    Two
    All four that I have purchased had a dipstick and no o-ring,

    I found the dipstick useless, because the oil vapors would hit the colder dipstick and give a high reading. Examining the cup of the catch can revealed only a small amount of oil and yellow mixture on the bottom.

    I replace the dipstick wit an M6x1.0 screw and an o-ring. That made the cup easier to screw off, since I did not need to unscrew and take out the dipstick first. The cup never fills much past the bottom of the cup, anyway, between oil changes.
     
    Mendel Leisk and Rebound like this.
  17. Rebound

    Rebound Senior Member

    Joined:
    Mar 11, 2010
    3,917
    2,525
    0
    Location:
    Portland, OR
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    Your explanation is the best so far. No sign of leak, very faint fumes… if the missing o-ring let’s out just a whiff of vapor, that could be exactly what’s going on. I’ll dig into it when I find the time. The OCC is underneath the car, so I need to jack it up and pull the belly pan. And no point until I get ahold of some o-rings.
     
  18. xliderider

    xliderider Senior Member

    Joined:
    Apr 19, 2012
    7,164
    2,717
    0
    Location:
    Honolulu, HI
    Vehicle:
    2011 Prius
    Model:
    Three
    If you don't want to get the o-rings, you can get some thread sealant like this. It's non hardening and can be reapplied as needed.

    I used it on all the fittings in my OCC installation. It's oil and gas resistant. It's available in a smaller tube as well, but the bottle wasn't much more so I bought the larger size. Screenshot_20211025-152325_Amazon%20Shopping.jpeg

    Posted via the PriusChat mobile app.
     
    Rebound likes this.
Loading...