Where to take car for rain/water leak diagnosis?

It’s rained a lot here lately and I have rain/water leaking in my trunk. Nothing is jumping out at me as an obvious problem (and I’m not very knowledgeable with cars), so I’m going to have to take it somewhere to properly diagnose the source of the leak.

My question is…what type of place should I take my car to? A mechanic? Body shop? Auto glass specialist? Other? I’m thinking body shop might be the right place to start.


I agree! Leaks are a body problem and those folks are the body experts. They will bring in the glass guys if they need them.


Thank you!

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Spoiler: If you have a sunroof, it’s probably the source of the leak. Most of them have drain tubes that can clog, and when they do the water flows into the trunk instead of on the ground where it should.

I have a sunroof but I don’t think that’s it. I used my hose and sprayed parts of the car and the issue seems to be somewhere on the back half of the car. And based on the particular area where I see and feel water collecting and dripping (it’s an area on the roof of the trunk), it looks like it might be a rear windshield or trunk issue.

theres a gasket ( SEAL) that goes around the trunk to make a seal when the trunk is closed. if its broken water will leak intro the trunk

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Yeah body shop but take a good look yourself. I had a bad trunk leak after having a trailer hitch put on. Couldn’t figure it out. Pulled the tail lights and re-sealed all the seams but leak persisted. Then discovered the guys wiring the hitch failed to replace a rubber plug in the back allowing tons of water in the trunk. Easy fix.

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You didn’t tell us the make, model, or model year of your vehicle, but if it was made by GM I can tell you that a lot of their vehicles had problems with water intrusion in the area of the rear windshield over the years.

Just to add, this should be fairly easy to find if its the rear window or the trunk. From the factory service manual, you take a hose and run water over the trunk seams to check for a leak. If none, proceed to the lower portion of the window and check if water seeped in. Just a low stream from the hose or the book uses a car wash type sprayer under low pressure.


Additionally, if the OP doesn’t detect water intrusion from the above-mentioned procedure, he should try directing the spray at the tail light area. If the vehicle is fairly old (we have no idea about the age of the mystery vehicle) the seals surrounding the tail lights may now have some dried-out voids that allow water intrusion.


The mystery vehicle is a 2004 Honda Accord. I’m pretty sure it’s not the tail lights based on where the water is collecting and dripping (the other side of the trunk door, on the roof of the trunk - right under the bottom part of the rear windshield).

Thanks for the responses. I may do some more testing this weekend if I have time. I’m bringing it to a local body shop next week.

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To a roadside car wash, usually for a fund raiser. Leave the fan on high. If the leak is obvious you will have a lot of bubbling coming out. Just wait for the wild laughter.

Interesting video. There is strip caulk and seam sealer available at you local parts house like NAPA to seal up any seams or to avoid having to make your own gaskets.

That certainly seems like my issue. Thank you for posting that. I may have to show it to the body shop.

I did some more testing and the issue seems to be higher up the rear window and along the back 6-10 inches of the roof rail (or whatever that’s called). The water still collects and drips in the same place as in this video though.

The worst leaking actually occurs when I really concentrate the water on the back part of the roof rail on the passenger side…just above the back quarter of the rear passenger window.

Are you talking about the roof molding?



Yes, thanks for clarifying.

Here’s how to remove it to check for a leak.


Thanks. I’ll probably leave that for the body shop to do but it’s still good to know.