Didn't find in search, but with how leaky these things are, I could have overlooked it! :P

Rained all day yesterday... backed outta the driveway... and there's lots of sloshing in the passenger rear.. A lot!

Not inside the door.

Dry on floor.

Took out back seat. Dry.

Took apart trunk. Dry.

If you make it slosh through acceleration or braking and get out.. it's coming out the drain tubes on the passenger side rocker panel.

Best I can figure out is the rear quarter window is leaking. Anyone else have this?

How do you take off the side panels in the back?

 

So basically its in your quarter panel and not in the car? If thats the case it can't be the quarter window because if that was leaking it would be in the car.

 

I don't know where it is... it sloshes a lot.... You can hear it very easily from the driver seat.. sounds like it's behind the plastic side panel in the rear seat.. everything on the inside is dry... wail on it and it's spilling out the rocker panel drains... I've been driving pretty hard, so it's just about stopped sloshing.

I'm a bit stumped.

 

Maybe inside your rockers.
Drain holes obstructed maybe?
You're saying it's not in the door... Did you take the panel off?
If you have the plastic plugs at the bottom of the doors, get rid of them, as they are useless and only cause clogging.

 

Rocker drains wide open... Stuck my knife in them.. nothin in the way..

Door does not slosh at all when you open it.. drains on it are open too..

Take off in first... slosh! slosh!! brake.. slosh! slosh!!

Wtf?

 

My brother has the same issue after it rains hard on his 2010, I am almost positive its not in your car I know his isn't. If it was behind the side panels it wouldn't be able to stay in there and it would be all in the car.

 

Ah.. found this picture of body in white... it's not coming from the quarter window...

I did drive about 100 miles in pretty hard rain.. must be a structural area of the frame filling up.. like if the seam in the wheelwheel or elsewhere is leaking..

Might try some exploratory drilling, or just make sure all the seams in the wheelwell are sealed good???

 

It should come out, my brother's usually comes out within a day or two.

 

Fixed! I took out backseat and both interior side panels. After removing seat belt spools to gain access to the voids in front of the rear wheels, I found a lot of water in each side. At least a half gallon per side. Now to figure out how it got in there. I used food coloring and made 4 different colors, a gallon of each. I started with the gap around the trunk lid using red. Nothing noticed inside the car. Then the gap along side the rear glass with green. Nothing. Then I used blue into the gap around the read side quarter glass. Bingo! Standing water in car turned blue. Repeat for glass on drivers side. Identical result.
With an 3/8" x 18" drill bit, I was able to drill a hole in the bottom of the voids (thru the standing water from inside the car). The bottom was not steel, plastic maybe?. All the water drained out of both sides. I completely dried the cavities and left the interior apart for a few days to air dry them further. I called a local glass shop, they ordered new glass for both sides and are replacing/resealing them Friday. (they probably could just reseal them, but insurance glass coverage requires replacement). Just happy not to hear the sloshing anymore!

 

Makes sense...these cars are not new anymore, urethane bonds get compromised.
Check your back glass as well.