Mildew under rear passenger carpet

Hi there. I suggest taking the car to a collision repair shop to obtain an estimate to replace the carpet. You're getting mold problems, and the easiest (and most expensive) way to take care of it is to replace the carpet. This of course is after resolving the source of the moisture.

You could have a plugged evaporative condenser, where the excess water is not draining. Have you noticed any puddles under the car after you have used the air conditioner (like "normal" cars would)? If not, you can have the drain blown out at any gas station (with car shop) or car repair facility.

Hope this helps.

 

I would expect that the mildew at the RR seating position would more likely be caused by a water leak in the hatch, not a problem with the AC system. Had the car been in an accident in the past? If not, perhaps it was parked in a low-lying area that flooded from winter rains, and water seeped from the RR door into the footwell area.

If the problem was attributable to the AC system then I would expect the carpet near the RF seating position to be affected first.

The best repair of the damage would be replacement of the carpet padding.

 

Yes if evap leak the front carpet pads would be moldy too. I hope you did not buy a flood damaged car. A car my buddy a car wholesaler calls a swamp car. Have you done a carfax on it?
So many cars damaged with flood damage up there. Is it a rebuilt title?
If the hatch is leaking easy to check. Just pull out everything to get to the spare tire. You'll have a puddle under the tire too.
But would also if flood damaged. Time for investigation work.

Good Luck!!

 

You could spray bleach on the mold to kill it. Not sure if that would eliminate the mildew smell thou. H

 

Hi!
I have exactly the same problem. After the last week heavy rain storm, I started to notice a strong smell. I identified yesterday the cause: the rear passenger carpet is wet. I thought that it was from our feet. But then I found the insulation beneath being even more wet, really wet. I read some posts around here and found out about the spare wheel check. I checked and found about one inch of water there too. So the compartment was not full ... then how did the water get under the RR passenger seat!? The 12V battery compartment has no water either. Honestly I am pretty amazed Prius has this kind of issue ... I only had this issue with my old Romanian Dacia car, designed back in 70s after a Renault model.

Now, did you ever found the cause and a solution to that? I will check the taillight gasket, but not sure how to make sure if that is the problem or not. As far as I know there was no incident involving my taillight. I was thinking to put some silicone around the taillight gasket (the exterior inner part that actually goes under the door and which is in the way of the draining water). Also, if the water is only under the RR carpet, should I check only the right taillight?

Then, how do I gain access to take out the insulation under the RR passenger seat (feet in fact). I understand I need to dry the under-carpet insulation and eventually use some bleach. Is it enough to take out the rear seat?

I found other posts similar, and some advices, but most of the people didn't report back to say if the fixed the issue.
Thank!

 

I just had the chance to do some work around ... I was able to get under the RR passenger carpet and saw where the water seems to come from the hatch. However I can't figure where the water gets inside there. I poured some water on the car ... nothing came inside ... I opened around the taillight and don't see anything wrong. Beside the spare wheel, I found that the 12V is half in water ... I still didn't get it out. The most annoying thing is that I don't know how to stop future leaks. I would put some silicone but I would have to just take guesses and put silicone everywhere. For now, I would just try to put something in the way getting from the hatch to the cabin.
Any positive experience would be helpful! Thanks!

 

Mine too stinks after rain....mildewy smell as well. I haven't checked the carpet though and definitely will the next time it happens. It would be a shame if these things had a leaking problem. Mine is a 2005 and out of warranty.

 

I had a similar issue with the car that I had before my Prius - a VW Passat. VW's have issues with their sunroof drains getting gunked up. I noticed this first just as I was out of warranty and the dealership was no help (surprise, surprise, VW's service is the pits). What I did a couple of times was to remove the back seat and then pull up the edges of the carpeting and padding. I then used old towels to soak up as much water as possible and then propped open the carpeting up to allow a bit of airflow to let the last of the moisture dry out. After about a week it was dry and I sprayed a ton of Lysol in before I put it all back together. A pain in the butt, but it worked fairly well.

 

Thanks! That's what I'm doing now ... I took out the car seat, then the rear seat, then pulled the carpet, took out the filling under the carpet to wash it ... and so on! But I don't want to do this after every heavier rain! I hope there is a more permanent solution.

And yes, mine is also 2005, out of warranty! It seems to me there is something systematic: battery compartment, spare tire compartment, RR passenger. I bought the car 2 years ago certified. I felt the smell before, but only now found the cause!

 

OK ... So last night rained (not too heavy, but quite long). The first thing I did I ran out to the car to see the water. Well, I think it's not the taillight, as found on other threads! The problem is that I still don't know for sure what is the problem.
Anyway I now understand why the previous owner traded in his Prius. Btw, did any of you traded in a light blue 2005 Prius to Star Toyota from Queens NY sometime at the end of 2008 or beginning of 2009. If so, then you are probably the previous owner of my Prius

I took some pictures, so if anyone can give me some suggestions, they will be more than welcome. Also, maybe someone may benefit from what we learn here.

First I noticed that on the left side the padding under the carpet is full of water and leaking (the carpet itself is dry).







And after I drove a little bit...







Now, let me show what I saw on the right side, where I pulled the carpet...

Here is where the water was leaking to the battery well...







Now, behind the carpet...








Now, taking out the upper molding...








OK. So now I am at the point trying to figure out what to seal with silicone. Plus I will try to build a silicone barrier at least to stop the water going under the RR passenger area. Please see pics and advise! Thanks!

https://picasaweb.google.com/116818493164304891612/Prius#

 

I never figured out where the water was coming from, but got tired of bailing out the spare tire well. I punched a couple of small holes in the rubber plugs under the spare tire (to allow water to drain) and have not noticed any adverse effects. (I have a leather punch - the holes are about the size of a belt buckle hole). I've no doubt that water is still getting in from somewhere, but at least it no longer sloshes about or contributes to any mildew problems.

 

Thanks! What about the battery ... you don't get water in there too? Or you punched that one too? ... it seems I have to get the battery out to make the punch.

 

Wow you have alot of water there. Most likley a crack in the body putty. Really bad leak like maybe more than one spot leaking?

Most common spot to leak is at the tailight but it seems your water line is much higher
also.

As far as the tailight if you open the hatch on the water channel where the top black plastic piece of the tailight meets the body water flows down the channel under that piece and past the tailight body. The slightest breach of the tailight sealant goop and you have a puddle in the trunk.

Sometimes hard to detect. One way to try is to hose the hatch down real good then open it up and see any tiny water trail leaking out the bottom of the tailight inside the car.

I have not had a tailight assy out of a Prius yet. Some cars are awful with black goop from hell (Sentra's!)

Maybe someone will way in how hard it is to take out that assy out because if its not to bad a complete and thorough re-goop is a real good place to start.

You gotta find it as it will continue to soak your carpet. Not to mention all that humidity inside the cabin and with all the hundreds of electrical connections in our cabin's thats a very bad thing. Everything will corrode and it will become an electrical gremlin car.

Until then a cheap abatement is an eBay car cover. You can get a nice one for $20. It will not be waterproof but will really cut down on the volume of rain the water channels will see. Spray it with Scotchguard and its amazing how much water it will shed.

One of my cars will not fit in my garage and I put a car cover on it everyday. Takes 2 minutes. Keeps the car really clean for days too.

 

Thanks! The taillight doesn't seem to be the cause. I looked very carefully inside after one night of rain (and still raining) and didn't see any water there.

Right now my best bet goes on the spot indicated by arrows in the pic. The rubber seems to be not very tight on the metal. When I pushed it from inside it snapped out really easy. I will do some tests to see is can verify this. I am not sure this is it.

Anyway do you have any suggestions on how to seal that? I am thinking to use some clear silicone, but not sure that's the best option. I am afraid that this will not hold and the leak will come again. Also I am not sure if I should replace the rubber pieces or not.

Right now it's sunny, so I left my car at home in the parking lot with all the doors opened and my wife guards it from the apartment's window I need to dry it!

 

Ok your probably right and since you suspect its higher thats easier to confirm. Put the seats down and lay in the back with a flashlight and have someone soak that hatch gap real good with a hose and see if you can see any leakage. With the headliner pulled down of course. I remember a post or two about cracked seams and failing body putty too.

Good Luck. You'll find it.
Il still like my car cover idea as that really cuts down on the velocity of rain hitting that channel.

BTW, the best stuff I have found to replicate body putty is Mighty Putty. It first sold at HSN as sticky putty . Its the only product HSN sold that actually worked. They were the fist to sell it now its rights have been sold and its everywhere as Might Putty. Its in all autoparts store. When mixed properly its like stone but seals really good and doesn't mildew. I fixed a cracked water channel seam in one of my cars with it. Its stupid but it really works. This stuff:

https://www.buymightyputtynow.com/flare/next?rtag=mightyputty&

 

Thanks! That's good to know (the mightyputty). For the cover ... I don't dislike it too much, but I'd keep this as a last solution.

I just found another thread where people have the same problem. I am trying to get some feedback from them since I am not sure I understand their findings ... http://priuschat.com/forums/gen-ii-prius-care-maintenance-troubleshooting/60295-water-leak-into-spare-tire-area-etc-2.html

 

Btw, is there any recommendation against using clear silicone (except I cannot paint over) as sealant. Do I need to go use some specific seam sealant?