Do I need to worry about these leaks?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Calloudyeah, Jan 12, 2026 at 11:41 PM.

  1. Calloudyeah

    Calloudyeah Junior Member

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    When i was doing an oil change, i noticed oil stain on the sensor and the bolt above the filter. Can someone tell me Is the leak from the senor itself or possibly from somewhere else, and what sensor is it?

    Is that bolt leaking too? and why is it look like half threaded?


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    #1 Calloudyeah, Jan 12, 2026 at 11:41 PM
  2. rjparker

    rjparker Tu Humilde Sirviente

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    It would help to have a long shot of the area for reference. First an "oil stain" is no big deal and could be from a small spill in the past. The thing to do is use brake clean or just soap and water and clean the area well. Check back a day after driving and look for a leak source, if any.

    Common active leaks are the timing chain cover where horizontal engine block sections meet and the sealant has slightly failed. Less common is the oil pressure switch or timing chain tensioner gasket. Don't crank the oil pressure switch down or you can break the aluminum it threads into.
     
    #2 rjparker, Jan 13, 2026 at 12:40 AM
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