Condensation on rear hardtop screen

  1. My model of MX-5 is: MK3.5
  2. I’m based near: London__
  3. I’m looking for technical help or recommendations on: condensation__

I’ve recently purchased a hardtop for my MX5 and have noticed that there’s water/condensation on the inside of the rear screen of the hardtop, Is this normal? The car is dry inside,
but there is some dampness in the boot which appears to be coming in from the wealded seam areas on the lip of the boot.


it may be that the car has a leak somewhere and water vapour within the cabin condenses at the coldest surface which is the glass. It could be that one of the drains is blocked, sorry I cant be of any more help on this.

On a side note, that If you want to clean the drains in an nc I wouldn’t stick anything from the top down. You cant clean them with a wire brush, you have to take the rear plastic out behind the seat. there’s a few videos on the internet that show how to do it.

Thanks for the reply. I’ve checked the car throughly inside and there appears no leaks inside the car, the carpets are all dry. The boot area is slightly damp with water somehow coming through the seams on the sides of the boot where water sits when the car is parked on a slope.

We’ve had a similar type of leak on another members car. It appeared there was a lack of enough seam sealer used on that car, or what was there had cracked, maybe it’s your problem too.


Water could be coming in from the third brake light and also the rear light clusters. Also from the rubber gromit which supplies power to the number plate lights, follow that back and fill with silicone. You can buy new rubber gaskets for all lights from mx5 parts.

Thanks for the replies.

The water/dampness in the boot appears to be coming from the seams where the boot is connected to the body of the car, as underneath this area are damp and the carpet directly underneath this area is damp. The grommet where a wire comes through has been sealed and the third brake light looks dry.

In the image attached this is the area that holds the water especially when the car is parked on a slope. The dampness is underneath this area and leaks on to the boot carpet,
you can see where I’ve lifted this up in an attempt to dry it out

You should also check the deck plates, they are the ones that you fasten the hard top to by connection to the Frankenstein bolts. Had a minor leak myself there, a quick tighten of the bolts stopped the leak.

Hmm, The paint where the hinge sits on the body doesn’t look quite right in that photo. I’ve zoomed into the pic to try for a better look.

Boot hinge bolt

It might just be a trick of the light, how it reflects, in which case please ignore this idea.

However, if the hinges have been off and were not sealed to the body when refitted, they are bound to drip, until the rust seals them for a while. Look at the nuts underneath and see if they show signs of wet or even rust.

Thanks I’ll check those two things tomorrow and have a good look at the paintwork.

If the water ingress is on that side of the car I would check the Ariel. My sons mk3 leaked vis this into the boot.

When the car is dry try CAREFULLY wetting the car with a hose starting at the lowest point and slowly work your way up. Check lights, boot lock, Ariel, 3rd brake light in a logical order. Take your time. Water will find a way in, Your job is to isolate where this is happening.

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Further to the paint work on the inside sides of boot area of my MX5, the paintwork is fine, it’s just the picture quality that make it look weird.

I’ve just put a jug of water around the aerial rubber seal, put lots of water in the channels of the boot and put water around the third brake light. I can’t see any water coming in, it’s parked on the road rather then our sloped drive, so I think this only happens when the car is parked at an angle down the drive when lots of water just sits in the boot channels, this all goes when I drive off the drive. Yes I could reverse on the drive, but I’d like to find out where the water is coming in,