oil pressure switch

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by darknd666, Apr 2, 2026 at 8:17 PM.

  1. darknd666

    darknd666 Junior Member

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    Whats going on here? Ill probably put some UV dye in the oil and see where its coming from.
     

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    #1 darknd666, Apr 2, 2026 at 8:17 PM
  2. BiomedO1

    BiomedO1 Senior Member

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    just spray the area around and above it with brake cleaner or degreaser. If it is the oil sensor leaking; they usually leak where the brass and plastic meet or around the electrical connector; there's a crack in the plastic portion of the sensor.

    Good Luck.....
     
    #2 BiomedO1, Apr 3, 2026 at 10:22 AM
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  3. darknd666

    darknd666 Junior Member

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    Thank you, more or less I was asking if this is where the mess "usually comes from". I have the cowls removed right now so easy access.
     
    #3 darknd666, Apr 3, 2026 at 12:01 PM
  4. rjparker

    rjparker Tu Humilde Sirviente

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    It usually comes from the timing chain cover seal. A common problem.

    Mine looked like yours until it was cleaned and then run for 30 minutes.
    Timing Chain Cover leak vertical.jpeg
     
    #4 rjparker, Apr 3, 2026 at 4:03 PM
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  5. darknd666

    darknd666 Junior Member

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    Now for an answer to a question I dont want to hear, do I have to remove the head to reseal the timing cover?
     
    #5 darknd666, Apr 3, 2026 at 11:05 PM
  6. darknd666

    darknd666 Junior Member

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    #6 darknd666, Apr 3, 2026 at 11:34 PM
  7. darknd666

    darknd666 Junior Member

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    Not a job I want to do but it is a job I can do. It looks mentally exhausting. Is there anything I can just seal it with externally? My Yaris leaks in the same spot on the 1NZFE motor. Where the trifecta of edges meet. I just let it leak, its not an inconsequential amount of oil between changes so I just live with it. I dont even get drips in the driveway.
     
    #7 darknd666, Apr 3, 2026 at 11:39 PM
  8. rjparker

    rjparker Tu Humilde Sirviente

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    I would clean it and verify. The head stays on but the chain tensioner comes off with the cover so you are essentially timing it on reassembly.

    Given a head gasket job in the future requires all of this again, I would hope for a seep or something easy and forget about it. Unless you have a value oriented skilled shop at your disposal. Which I did.

    One guy this week got a quote for well over $3k from a dealer. By the book this is an engine out repair because you have to butter up the cover and block seams and install in 3 minutes without smearing it and have it completely torqued in 15 minutes. Even then the factory seals give out. Toyota redesigned this mess on later generations.

    Some suggest clean it, locate and fill with form a gasket. It's a tough place to see; much less to get to with some kind of sealer.

    Isolated reports of tensioner gasket fails or oil pressure leaking through the switch exist. Don't over torque the switch or you will really have issues.

    This is not your father's engine.

    By the way, the reseal video above was good. He did show a page out of the official procedure. Toyota has another way to release the tensioner so read the manual. I have seen two other methods including his.

    Ending up with rework because the timing is off creates a bad day. It is often caused by not manually releasing the tensioner or allowing slack on the opposite side. Machining the head too much can also do it and may leave no way out. That can ruin your week.
     

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    #8 rjparker, Apr 4, 2026 at 12:25 AM
    Last edited: Apr 4, 2026 at 1:57 AM
  9. darknd666

    darknd666 Junior Member

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    UV dye at harbor freight is relatively cheap, that said with cleaning the oil and crud off, or even without, it should be painfully evident where the leak is. I am confident knowing this is a problem area on the 1NZFE in my yaris. If I clean it well enough I might spray some sealant or something of the sort to help it out. Maybe change the oil to a high mileage formula to help swell the gasket material and slow it enough to where it isnt a problem.

    My 2007 Yaris does not lose any oil between changes and has the oil spot in the same place.
     
    #9 darknd666, Apr 4, 2026 at 12:35 AM
  10. rjparker

    rjparker Tu Humilde Sirviente

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    There is no gasket material to swell up other than Silicon RTV gasket maker sealant.
     
    #10 rjparker, Apr 4, 2026 at 12:44 AM
  11. darknd666

    darknd666 Junior Member

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    Doesn't Mobil 1 high mileage have additives for that?
     
    #11 darknd666, Apr 4, 2026 at 12:46 AM
  12. rjparker

    rjparker Tu Humilde Sirviente

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    It won't work on rtv and its a bad idea for other polymer seals you don't want to start restricting oil flows.
     
    #12 rjparker, Apr 4, 2026 at 1:40 AM
  13. darknd666

    darknd666 Junior Member

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    So high mileage oil is actually bad for this engine?
     
    #13 darknd666, Apr 4, 2026 at 2:01 AM
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