Oil leak on plate next to exhaust manifold

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by oldtechaa, Apr 10, 2020.

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  1. oldtechaa

    oldtechaa Active Member

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    First off, a disclaimer that this isn't technically about a Prius. It's actually about a Corolla, but it's essentially the same engine as the 2ZR-FXE. Here's a picture.

    upload_2020-4-10_14-56-54.png

    To the right of the exhaust manifold, two bolts can be seen holding a plate on. Everything from that plate down is covered in oil. Does anyone know what the plate is?
     
    #1 oldtechaa, Apr 10, 2020
  2. The Critic

    The Critic Resident Critic

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    The picture is a bit dark, but I see both engine oil and possibly cv boot grease. Before continuing, I recommend degreasing and pressure washing the area.

    Most likely, it is seepage from the timing cover but there have been some reports of oil seepage from the timing chain tensioner gasket. The timing chain tensioner gasket is metal so the likelihood of oil seepage/leakage is very low.
     
    #2 The Critic, Apr 10, 2020
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  3. Mendel Leisk

    Mendel Leisk MMX GEN III

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    I think that plate with the two bolts is the timing chain tensioner? It sure looks the likely source. Do you know it's ever been removed? I recall in the latest Gasket Master video they say to replace its gasket or risk leaks.
     
    #3 Mendel Leisk, Apr 10, 2020
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  4. The Critic

    The Critic Resident Critic

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    Why would a metal gasket leak?
     
    #4 The Critic, Apr 10, 2020
  5. Mendel Leisk

    Mendel Leisk MMX GEN III

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    Don't know, but pretty sure they said something about that.
     
    #5 Mendel Leisk, Apr 10, 2020
  6. oldtechaa

    oldtechaa Active Member

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    Thanks for all your comments. It looks like it is the timing chain tensioner, but according to a video online, which looked very much like the 2ZR-F(X)E, it is a simple rubber o-ring gasket. That's the highest point you can see oil, although the highest point I could see oil actually dripping while the engine was running was the electrical connector (probably a sensor) below the connector in the lower right of the picture. I do not know if it has ever been removed, but it looks like it's not uncommon for it to start leaking.
     
    #6 oldtechaa, Apr 10, 2020
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  7. The Critic

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    The 1ZZ-FE's (old 1.8L in 03-08 Corolla) used an o-ring on the timing chain tensioner. The 2ZR 1.8L (09+ corolla) used a metal gasket, part # 135520T020.
     
    #7 The Critic, Apr 10, 2020
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  8. oldtechaa

    oldtechaa Active Member

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    Yeah, I was just looking it up, and I see that. That's interesting. It seems that it's not uncommon for it to leak even so, however.
     
    #8 oldtechaa, Apr 10, 2020
  9. The Critic

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    The old ones leaked quite regularly, I have changed a number of them.

    The metal ones rarely leak. Not saying it does not happen, but it is rare. The tensioner is in such close proximity to the timing cover seal that any oil seepage from the timing cover can be confused with a tensioner gasket leak.
     
    #9 The Critic, Apr 10, 2020
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  10. oldtechaa

    oldtechaa Active Member

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    OK, I'll have to do a bit more digging. I do have 2 much closer angles here, though.

    I'll try cleaning the area and see if I can see exactly where it comes from. Thanks for your help.
     

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    #10 oldtechaa, Apr 10, 2020
  11. Mendel Leisk

    Mendel Leisk MMX GEN III

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    Gasket might even be missing??
     
    #11 Mendel Leisk, Apr 10, 2020
  12. The Critic

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    To me it appears to be seeping from where the block, cyl head and timing cover intersect. There is a larger seem there that requires a bit more rtv to seal.

    But since it is dirty, hard to say.
     
    #12 The Critic, Apr 10, 2020
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  13. Mendel Leisk

    Mendel Leisk MMX GEN III

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    OP's clean up an monitor will hopefully clarify.

    Is it a big deal to remove the timing chain tensioner and replace the gasket? Would you need to crank the engine counterclockwise a bit to release it?
     
    #13 Mendel Leisk, Apr 10, 2020
  14. Mendel Leisk

    Mendel Leisk MMX GEN III

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    Timing chain tensioner install info:
     

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    #14 Mendel Leisk, Apr 10, 2020
  15. oldtechaa

    oldtechaa Active Member

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    I was thinking about just replacing the tensioner gasket since it's cheap and easy, but that looks a little more difficult than I thought. Does the timing cover have to be removed? That's kind of how it looks, but in the video I saw it wasn't necessary. I'll clean and run first, probably tomorrow, then report my observations. Here's one more picture showing the connector that was dripping and everything from there up to the tensioner. Thanks for your help and the repair manual pages.
     

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    #15 oldtechaa, Apr 10, 2020
  16. The Critic

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    Tensioner comes out fairly easily - just two bolts. Best practice is to put the engine at cyl 1 TDC to make sure it does not jump time, but most people skip this step.

    The oil pressure switch can sometimes drip. That is probably a more likely leak point than the tensioner. The switch comes off with an adjustable wrench. I usually use thread sealant on them but I think Toyota specs something else.
     
    #16 The Critic, Apr 10, 2020
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  17. ASRDogman

    ASRDogman Senior Member

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    Oil pressure switches usually leak where the metal is crimped over the plastic because of the
    heat/cold cycle and the plastic get hard and cracks. If you pull the rubber cover off of it, it's probably full of oil.

    Best to gunk it down(cold engine), how it off, blow dry it if you have a compressor.
    If not, try to dry it with a rag, or let it sit with the hood open to dry, then drive it a few miles to warm it up.
    Then check everything.


     
    #17 ASRDogman, Apr 10, 2020
  18. oldtechaa

    oldtechaa Active Member

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    You're all correct. It is the oil pressure switch. I have a new one coming from RockAuto. The dark area around the head gasket and tensioner must just be seepage over time, but the oil pressure switch was clearly leaking out the connector. Thanks for your help. I'll leave an update if I have any problems.
     
    #18 oldtechaa, Apr 11, 2020
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  19. ASRDogman

    ASRDogman Senior Member

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    You're welcome. I've seen a lot of those leaking. Oil goes EVERYWHERE!
    The one on my Town and Country leaked a lot. I was really amazed at just how much
    oil can leak out of that thing!

    Just gunk it down good after you change it. And clean out the rubber boot cover and connector.
    You could still have another leak, but the pressure switch was probably the worse leak. And you may be
    able to live with a different leak. I've used silicone, and rubbed it over seeping leaks to stop them.
    For a while anyway... :)

     
    #19 ASRDogman, Apr 12, 2020
  20. Mendel Leisk

    Mendel Leisk MMX GEN III

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    Info on oil pressure sensor:
     

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    #20 Mendel Leisk, Apr 12, 2020
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