Leak in trunk??? [Archive] - MX-5 Miata Forum (2024)

MX-5 Miata Forum > NA/NB (1990-2005) Miata > NB (1999-2005) General discussion > Leak in trunk???

PDA

View Full Version : Leak in trunk???

99mx5kid

30th July 2008, 11:12

So in my nb when it rains it will leak but only sometimes usually when it rains really hard. The water builds up only on the driver side in that little pocket and it spills over into the spare so i had to remove all that stuff. Any One have an idea how i would be able to find the leak or have had the same problem to there car?

smustang1234

30th July 2008, 11:22

Not much help ,But is the drain in gas cap well clogged?

Racing_Green

30th July 2008, 11:40

I think that pocket bolts in too. If you can remove it, check to see if there is a seal of some kind. You might replace it or apply some caulk or weather foam to it.

Flyin M2

30th July 2008, 12:25

Rain rail drain. Driver side is clogged.

Racing_Green

30th July 2008, 12:32

Rain rail! Right, defintely check it.

99mx5kid

31st July 2008, 01:37

how would i go about checking the rain rail??? dont pay attention to it never thought i would have problems

smustang1234

31st July 2008, 01:51

Take a water hose, and run water in seam between the top and drivers side. If water is not draining underneath the car, near the jacking point The drain is bad, clogged. The gas cap area, same thing run water in see if drain works. If not take hose and place over drain hose and flush out.

millers1

31st July 2008, 06:46

Put the top down. Look behind (towards the back of the car) the seatbelt mount, you should see a small hole. Might be a leaf or something blocking it. I used a small wire to carefully punch out blockage.

Flyin M2

31st July 2008, 12:16

Quick search will pull up a plethora of threads/posts on how to properly clean the drain.

99mx5kid

31st July 2008, 15:33

so i checked them all and they are all clear the water comes out the bottom of my car right by the rear lift points on both sides and the gas tank drain thing is the same way. what else could it be

dfitz

31st July 2008, 16:00

You haven't told us what sort of tests you have done and if as a result of those tests water got in OR is water only getting in while driving in the rain?

We have a 2003 so the inside of the trunk may be different than your 1999. On ours, on the driver's side of the trunk, there is a plastic bin that has a screw in the bottom. It would take a lot of water to fill that bin to overflowing. Having said that and having had a look at where the trunk lid hinge bracket ends up when the lid is closed, it seems that any entering water could follow the left hinge bracket and fall into the bin. Can you test for the leak with the lid closed, then open the lid and see if the bracket is damp. This might be a clue as to the origin of the leak.

Are you sure the trunk gasket/seal is fully on and seated properly with no cuts or splits? As an experiment to see if it 'mates' to the underside of the trunk lid use some contrasting (to you car's colour) lipstick on the top of the gasket, close the lid, open it and check to see that there is smudged lipstick ALL the way around. Sometimes using powder will do but is not as good an indicator.

As to running water so it will go down the rear drain holes as an indication they are not blocked is only part of the process. Find them and use something small and flexible to gently push all the way through to the bottom to ensure any 'crap' that water could ooze by and thus flow out is cleared.

Those are my thoughts on this and I, like many others I'm sure, await the answer to your problem - good luck!

coldwarrior

1st August 2008, 00:28

if a miata is parked facing uphill at a high enough nose up angle the trunk will fill with water even though the drain plugs are clear.

dont ask me how i know.

doctorbonez

1st August 2008, 09:50

Some options to check out a leaky trunk I managed to score on all 3!

As others have mentioned, check the rain rail. Search for more details. Mine was cracked in multiple places and flooded my trunk every time it rained hard. I fixed it by taping it on both sides with tent tape from walmart. Fixed it 2.5 years ago and it still hasn't leaked.

Check the grommet on your antenna. I have a 99 with the wire antenna and somehow the rubber grommet was alittle loose.. this was just a small leak, but it was enough that i can see rivulets of water running down the side of my trunk when i washed the car. I just put alittle silicon around it to seal it up.

If your car has ever been in a rear ender, or you had the rear quarter panels repaired, there is a chance it is leaking through the seams of the repair. My car had the driver side rear quarter panel repaired very early on in its life.. and there is a seam between the car and the new metal that lies under the gutter of trunk lid.. water was dripping into the trunk everytime it rained hard. I never determined exactly where the leak was, but I put some silicon (and rubbed it in) and it hasn't leaked since.

good luck and let us know what you find!

jkent59

1st August 2008, 10:01

if a miata is parked facing uphill at a high enough nose up angle the trunk will fill with water even though the drain plugs are clear.

dont ask me how i know.

We have an inclined drive and what you say is very true. If it looks like rain I back in and no troubles.

99mx5kid

3rd August 2008, 19:39

ya my drive is inclined to ill try backing it in next time its gonna rain and see how that works.

Gort

3rd August 2008, 20:27

99MX5KID - If the drains are clear and flow water when you test them, then it could be a tear in the rain rail.

Not much help ,But is the drain in gas cap well clogged?

AFAIK the gas filler drain exits outside of the car. Otherwise a gas overfill would end nup in the trunk.

Peter

smustang1234

4th August 2008, 00:07

Gort, I hope all drains run to outside of car. Your point is good though, But if the drain had hole or was missing. It would seem to be in right location to leak in to trunk.

Parramore2000

4th August 2008, 15:06

if a miata is parked facing uphill at a high enough nose up angle the trunk will fill with water even though the drain plugs are clear.

dont ask me how i know.

How right youo are. I found out the hard way. Now, when we're expecting a downpour, I back the car into the driveway, with the tail up. Problem solved.

95 NA

cmga64

24th September 2012, 18:18

Gents, I have noticed the same problem with my 99 Miata. However, I am looking at a different approach and would like to get some feed back, if possible. After removing the tin shiels covering the gas tank hoses, I noticed there was some corrosion on the aluminum plate. When further investigation to how the water was puddling there, I looked above and that is where the chrome plate with the two screws is mounted. This is the small plate where the hardtop mounting bolt goes on the deck. There is a rubber seal underneath nthe chrome plate. When I removed it I noticed it was torn and the threads of the outer screw had rust. I suspect the water is getting in through the threads of the screws. Any thoughts would be greatly appreciated.

MaxDoubt

27th September 2012, 15:18

I had water in trunk due to debris (tree leaves mostly) in the rain rail channel blocking water flow. Cleaned it out with flexible rod but ended up cracking RR. Repaired with walmart tent tape or vinyl tape and solved problem. No leaks for 60K.
Also check seal around rear lights.