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Huge water leak in back of 2004 Prius

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by priusrecon, May 3, 2015.

  1. priusrecon

    priusrecon Member

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    I just found a HUGE water leak in the back of my 2004
    Prius.

    It came in when I sprayed the hose down the back of the
    rear liftgate window. It seemed to be flooding into that
    little bit of stamped sheet metal running along under
    the window base, and just literally poured out the center
    hole, landing into my spare tire well. It was so bad I
    wondered if there might be a whole part missing up in
    there.

    Anybody know how to stop that leak?
     
  2. exstudent

    exstudent Senior Member

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    This is a well know problem for Gen 2, and there are multiple threads about this problem.
    Had you searched "water spare wheel," you would have seen many postings.

    These two threads are good. Read throughly to understand how to find the leak(s), how to fix, and there will be no more questions.
    Water filling driver side floor pan. | PriusChat
    Water leak...into spare tire area etc | PriusChat

    If this car was in a rear end accident, the accident may be contributing to the leak too.
     
  3. bisco

    bisco cookie crumbler

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    oh boy. i never had any water in my '04, sounds like somethings not right.
     
  4. priusrecon

    priusrecon Member

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    Tried searching both "water leak" and "water leak back of" and got no results even nearly relative.

    Thanks for the steer, but none of those posts describe the leak location I'm having.

    How do you remove what looks like the plastic spoiler wing that separates the top glass of the
    rear gate from the back vertical glass. When I soaked the top glass, the water appeared to
    be pouring out from underneath there. Tomorrow in daylight I'm going back out there with the
    hose and some wrenches. The leak happened as I was spraying directly onto the top rear
    gate glass.
     
  5. bisco

    bisco cookie crumbler

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    some people have cracks in the rain gutter weld, others in the hatch hinges, but it sounds like yours is lower. have you checked the 12v battery area, the spare tyre well and the hybrid battery case for water?
     
  6. priusrecon

    priusrecon Member

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    Had the car 3 weeks now.

    Spent the last 5 days stripping out the entire car's interior trim and seats, cleaning out the rodent infestation and about 10 years of rotting food & s**t dropped by the slobby kids of the previous owner. Removed all drainplugs and thoroughly soaped and hosed out the whole body shell of the car. Is spic n span now, even smells great. Battery compartment as well as whole back of car was all gunked up from decaying leaves maybe(????), but had been dry. Only what looked like old dried up rodent droppings & broken glass cubes in the spare tire well.

    Thought it might have been a Sandy Storm recovery, but all the sheet metal cleaned up nicely, no rust. I noticed the left side B-pillar glass trim piece had been wet inside when I removed it last week, thus the spray test today. But the only leak I found today was that massive one at the center of the base of the liftgate.
     
  7. brucebee

    brucebee Junior Member

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    dont spray the hose down the back of the window, just sayin
     
    theshark likes this.
  8. bisco

    bisco cookie crumbler

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    window gasket, or lower?
     
  9. dolj

    dolj Senior Member

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    Cute, but not helpful. How do you tell the rain to not fall on the rear hatch? :D
     
  10. exstudent

    exstudent Senior Member

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    You definitely have a very different leak pattern.

    Remover all rear interior paneling (trunk and hatch) to trace the water leak. Helpful to have someone spray while while you look for leaks w/ a flashlight.

    Wonder if the rear hatch glass wwas replaced, but poorly installed?

    Good luck and report your findings. Might help another person down the road,
     
  11. 69shovlhed

    69shovlhed Surly tree hugger

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    ^ +1. one of the windows in the hatch was broken and not replaced correctly.
     
  12. priusrecon

    priusrecon Member

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    Leak Solved.

    Pulled rear spoiler plate off, the one joining the two pieces
    of window glass on the lift gate.

    Found there to be no appearent seal from the back of the window
    to underneath the front of the spoiler plate. Don't know if that's
    Toyota's design, or the oversight of the guy who replaced the gate
    glass.

    Also found the foam sealing grommet around the HCSL wires into the
    spoiler to be displaced. See the pictures below....

    Also found there was some sort of spongy tape seal around the BACK
    edge of the spoiler plate that looked like it did more harm than good,
    as it wicked up water and held it there indefinitely, and could only
    serve to promote rust with time.

    [​IMG]
    prius_water_entries_gate1_480
    by
    osukent302, on Flickr


    [​IMG]
    prius_side _drip_spots_480
    by
    osukent302, on Flickr


    [​IMG]
    prius_landing_spots_side_480
    by
    osukent302, on Flickr


    [​IMG]
    prius_spoiler_fasteners_480
    by
    osukent302, on Flickr


    [​IMG]
    prius_rear_gate_foam_seal_480
    by
    osukent302, on Flickr


    [​IMG]
    prius_rear_gate_leaks1_480
    by
    osukent302, on Flickr


    [​IMG]
    prius_hairline_cracks_480
    by
    osukent302, on Flickr


    If this is Toyota's design, then if that little foam sealing grommet
    around the wires isn't properly applied, then that is the cause of so
    many rear trunk, spare tire well, battery comparment, and rear seat
    footwell leaks.

    As it was; as water ran down the back window, it dove under the spoiler
    plate unimpeded by any rain guard, and was trapped under there by the
    rear spongy seal. As it pooled up, it simply ran through the openning
    left by the displaced grommet, into the stamped doubler running
    underneath the rear of the liftgate, and poured out the hole under
    the wire opening into the rear trunk space.

    Also found 7 other potential leakage points under the spoiler plate,
    that if the factory installed seals aren't right, would lead to lots of
    water entry - 4 bolt holes, and 3 plastic snap fasteners with insertion
    points through the sheet metal of the liftgate.

    Also found two leakage points near where the liftgate pistons bolt to
    the car body. Interestingly, the bolt holes weren't the problem, it was
    the tiny microscopic hairline cracks around where it seems sealant was
    applied to cover the weld patch under the bolt on points. Water would
    seep in throught these almost invisible cracks, and run down the interior
    doublers under the side rims of back hatch, where it would drip out of
    two holes, run down the inside of the interior trim, and land on the
    trunk floor.

    After reading so many other's complaints about, and theories
    about leaks in their Prius's, this water source makes sense for all
    of them. As this water leaks in, it accumulates in the spare tire well,
    battery cavity, and upper floor of the trunk well, where it then runs
    forward each time breaks are applied, ending up in the back seat
    footwell spaces.

    The Fix -

    Remove the rear spoiler plate & thoroughly clean out all the accumulated
    silt and crap trapped under there.

    Examine the round foam grommet sealing the center stoplight wire bundle for
    proper placement. I got a replacement round rubber grommet from the hardware
    store and pressed it into the hole as a replacement. Had to dremel tool out
    a small tab in the plastic to allow it to fit inside the hole.

    Assure all 7 other hole seals for the liftgate tail section are intact. Apply
    silicone sealant if needed. CLEAN the sheet metal and plastic surfaces first!

    Remove the rear sponge seal tape if it is there. It just makes things worse.

    Install a front edge seal for the spoiler plate. I did so by buying some vinyl
    bulb seal tape from the hardware store, cutting it to the length of the leading
    edge of the spoiler. Made a slight notch for the grommet around the wire entrance
    hole. I simply laid it along the base of the rear edge of the window glass, and
    after tucking it under the leading edge of the spoiler, socked the spoiler into
    place with the plastic fasteners and the 4 bolts. Didn't need any glue or sealing
    paste, it's sealed by the clamping force of the leading edge of the spoiler plate
    against the sheet metal of the liftgate itself.

    After removing the spongy tape from the back edge of the spoiler (and before the
    above installation), I taped short sections of the bulb tape in it's place to act
    as an immobilizer in case the spongy tape's purpose was to stop any rattling or
    squeaking between the metal and the plastic parts. Leave wide gaps between each
    piece so they don't trap and pool the water underneath the spoiler.

    Used a tube of clear sealant to bead around the entire leading edge of the rubber
    seal on the rim of the liftgate. Also covered those microcracks mentioned earlier
    with electrical tape and sealed them with sealant.

    After this, I flushed it thoroughly with the hose for 5 minutes and not a drop of
    leakage anymore. Whole fix cost $8 in materials and 20 minutes of craftsmanship.


    [​IMG]
    prius_rear_water_guard_480
    by
    osukent302, on Flickr


    [​IMG]
    prius_top_edge_seal_480
    by
    osukent302, on Flickr
     
    Hesham99, RickyV12, ftl and 2 others like this.
  13. exstudent

    exstudent Senior Member

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    Good job tracing down the leak, and writing a detailed fix with diagrammed pictures. This will benefit all Gen2 owners as another source of water entry to investigate (rear spoiler area and hatch strut mount bolt area), esp if any window or spoiler work (removal/reinstallation) was done on the rear hatch.

    This water location entry is the first I have encountered here on PC. All other water entries I have read about, have come from the hairline crack(s) near the hatch hinge, at the base of the black roof molding, unless an accident repair was first ruled out. The usual fix of applying a sealant to the the roof hairline cracks worked, as people reported no further water entry.

    Bottom line, you solved the leak, and now we know of an additional area to rule out. Chew out the person/company who did the shoddy repair as they screwed up in my opinion.

    EDIT:
    Just dawned on me that the "spongy" tape you referred to earlier, reminds me of the "spongy tape," used in the front cowl area. When this spongy tape goes bad, water usually drips onto the cylinder head, entering a spark plug well, causing issues.

    You may have already thought of this, but the big box hardware stores sell weatherstripping in various widths and thickness. You could possibly make your own "spongy tape" seal, using a RUBBERIZED weather stripping. Don't get the FOAM weatherstripping, as it doesn't hold up as well.
     
    #13 exstudent, May 18, 2015
    Last edited: May 18, 2015
    RickyV12 likes this.
  14. BronxNua

    BronxNua New Member

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    How did you remove the liftgate ? to seal it?
     
  15. BronxNua

    BronxNua New Member

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    I mean the spoiler.
     
  16. BronxNua

    BronxNua New Member

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    My 2009 has so much rusting due to the water? did you guys have the same ?
     
  17. bisco

    bisco cookie crumbler

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    where is the rust?
     
  18. BronxNua

    BronxNua New Member

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    inside where the bumper connect to the rear., the battery area, the casing of the batter pack, The seat brackets on drivers side and passenger.

    I put caulking under the rubber of rear, I put silicone on the tail connector, the back light bottoms that water would run into trunk, I had no water after a big rain, I forgot to check the battery well, that was full of water. Got the water out and installed the new battery.



    I had to change my 12v Thursday due to the 12v failing to keep charge. I had charged it and took it for a long ride, it working Thursday morning, when going home from work, it failed. I had my portable battery booster so I got home and changed it. Been working fine now.
     
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  19. bisco

    bisco cookie crumbler

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    there are threads here on water getting in through gutter seam cracks, hatch hinges, and etc.
     
  20. Hesham99

    Hesham99 Junior Member

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    Thanks you help me alot

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