Huge water leak in back of 2004 Prius

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?

 

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.

 

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.

 

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.


prius_water_entries_gate1_480 by
osukent302, on Flickr



prius_side _drip_spots_480 by
osukent302, on Flickr



prius_landing_spots_side_480 by
osukent302, on Flickr



prius_spoiler_fasteners_480 by
osukent302, on Flickr



prius_rear_gate_foam_seal_480 by
osukent302, on Flickr



prius_rear_gate_leaks1_480 by
osukent302, on Flickr



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.



prius_rear_water_guard_480 by
osukent302, on Flickr



prius_top_edge_seal_480 by
osukent302, on Flickr