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Trying to figure out this oil leak.

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Higgins909, Feb 14, 2023.

  1. Higgins909

    Higgins909 Member

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    2010, 193k miles. It's been going on for a while. It gets worse when I tow. I thought it was the pressure sensor but after I went to go see if I had a big enough socket (couldn't even get the connector off) I thought maybe it wasn't after all. (I ripped apart the egr, IM, TB, and cleaned)

    I've heard the timing chain gasket is a problem. I was hoping it wasn't after googling that it might be the pressure sensor/switch. So I go and look in there and this is what I see. The bottom red is the oil pressure switch, the top red is some sort of hole with a sort of plug in it, but then there is a hole in that plug? I was really wondering about this, because the green circle, the cable mount pretty much right behind it and all the way down the wire that is mainly hidden was covered in oil and grit the most.

    In the picture I had already tried to clean it up a little bit and after that I tried to clean it up some more. When towing, I'm probably going through 1qt in 200 miles but when I'm not, I maybe get 1000 miles a quart. It really depends. There have been long roadtrips where I virtually lost no oil. The lake is a 55mile round trip, so I'm not in any danger but I do find it quite annoying to top off so much.

    Does anyone know why it's leaking and if it's related to that possible hole by the cable mount? It's hard to see it from the other side and it's not really dripping but a seep.

    Thanks,
    Higgins909
    Prius oil leak.jpg
     
  2. ASRDogman

    ASRDogman Senior Member

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    Toyota strickly says NOT to tow anything. The car was not designed for towing.
    There are those that do, but that doesn't make it right.
    You would not lose much oil from a timing cover leak. Seepage usually.
    The oil pressure switch does leak a lot.
    Best thing to do is Gunk the whole engine, rinse it off and let it dry. Then drive it and
    check often for any leaks.
    With those miles, good possibility the oil rings are allowing oil to pass through. Which is common.
     
    Grit and Higgins909 like this.
  3. nicoj36

    nicoj36 Active Member

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    You need BG hybrid repair kit. Eliminates oil consumption.
     
  4. ASRDogman

    ASRDogman Senior Member

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    No it doesn't.... I tried it, it did nothing....
     
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  5. Higgins909

    Higgins909 Member

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    Until I'm able to get a look on the backside of my engine, any thoughts on a timing chain tensioner causing the leak? That's supposedly right next to the hole I talk about in the top red circle.
     
  6. nicoj36

    nicoj36 Active Member

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    It did for me and other prius owners. Just read the reviews on Amazon. Search ‘bg hybrid repair kit’.
     
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  7. tankyuong

    tankyuong Senior Member

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    i say your prius is burning the oil through the piston rings
     
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  8. rjparker

    rjparker Tu Humilde Sirviente

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    BG might reduce oil burning slightly due to stuck piston rings but you will still have a quart every thousand miles. Can easily run out of oil in less than 4,000 miles.

    A small gasket or oring gasket leak does not cause a major oil consumption problem that varies between a quart every thousand miles or a quart every two hundred miles under load.

    Gen3s have a Toyota acknowledged problem with low tension piston rings that often cause excessive oil consumption. A production change occurred in mid 2014.

    Toyota replaced 2010-14 pistons and rings free if consumption exceeded a quart every 1200 miles. Regardless of load. This program has expired on all gen3s based on time alone. But the bad pistons and rings are still with us. Which is why you hear us say change the oil every 5k miles like your wallet depends on it. From day one. Once they are worn high loads will increase the consumption. No chemical bs will fix it. Clogged egrs, liquids in the intake and blown head gaskets are direct results. Those systems were revised in 2016.

    The only real fix is a rebuilt engine that includes new pistons and rings. A new intake should be included, it was revised as well. Use a cleaned egr cooler and valve. The rebuild will seal all the seeps. Then change oil often.
     
    #8 rjparker, Feb 15, 2023
    Last edited: Feb 15, 2023
    Doug McC likes this.
  9. Mendel Leisk

    Mendel Leisk Senior Member

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    Id say carbon clogged EGR is due to its design. It happens with or without oil consumption.

    liquids in the intakes are due to PCV design. I’d speculate the intake of a 2015 would also have a pool at the bottom.

    my 2 cents: the head gaskets are blowing due to EGR carbon clogging, in particular the propensity of the EGR passages to clog successively, commencing with cylinder one.
     
  10. Higgins909

    Higgins909 Member

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    After trying to look at it better, it looks like it might be the head gasket on cylinder #1. In the picture, you see the exhaust manifold to the left and the right is what I think the timing chain tensioner is. I tried to clean it up with some wd 40 degreaser I had, then drove it almost 2 weeks. About 140 miles. Didn't tow again, yet. No noticeable oil loss. Not sure if the oil looks so messy because I tried to clean it off or not.

    I wonder if this is the common spot where they fail.
    IMG_20230225_21480765.jpg
     
  11. rjparker

    rjparker Tu Humilde Sirviente

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    People have seen leaks at the tensioner and the timing chain cover. Has this car had a head gasket job?
     
  12. Higgins909

    Higgins909 Member

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    As far as I know, no. I cleaned up the EGR stuff, intake man., throttle body around 187k. 12v battery around 2-3 years ago. Replaced either front or rear pads, even though they were fine. Spark plugs and air filter. PCV valve. Did the "transmission" oil as well. Would have to go though my book for dates, but all of this is in the last 3 years.
     
  13. rjparker

    rjparker Tu Humilde Sirviente

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    Some would clean it again and put florescent dye in the oil to id the spot.
     
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  14. ASRDogman

    ASRDogman Senior Member

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    What you need to do is Gunk it down really well in that area. Then use a spray
    hose of water to wash it away.
    The oil pressure switch is a common leak and will spread oil everywere.
    The air will blow it all over making it hard to pin point.
    You wouldn't think it would use so much oil and make such a mess, but it does.

    You can pull the rubber cover off the pressure switch and you'll probably find that
    it is full of oil. They are about $15 and fairly easy to change.

    After you've clean it up, drive it and check for leaks often. If you look really closely
    you should be able to see where the oil if leaking from.