Z3 Boot Condensation

Gatsoburner

Gatsoburner

Zorg Legend
British Zeds
Joined
Dec 16, 2025
Points
73
Location
North West of UK
Model of Z
3.0i
Anyone tackled the issue of damp in boot lid after cold nights.?.

Im considering adding some closed cell insulation, reading up it appears it'll be a barrier to the cold air accumulating overnight.

I'm going to give it a go overnight then take it off and see whats what, opinions??....
 
You probably need to make sure there is no dampness already in the boot as that's where the water to form the condensation is coming from.
The usual suspects for leaks are the aerial grommet and the 3rd brake light seal. Very rarely the light units seal.
 
Gatsoburner said:
Anyone tackled the issue of damp in boot lid after cold nights.?.

Im considering adding some closed cell insulation, reading up it appears it'll be a barrier to the cold air accumulating overnight.

I'm going to give it a go overnight then take it off and see whats what, opinions??....
Click to expand...
I think the problem is related to your other thread regarding the roof and water in the boot.

Unless there is water present in the boot you can't get condensation on the inside of the bootlid. Insulation ain't gonna fix the problem, just divert it to elsewhere.

As I'm sure you are aware, electrics and moisture do not go well together. And there are a lot of electrics in the boot of a Z3; not least the battery!
 
All points in the boot are dry, no dampness in any corners or floor, I check it every time I open the boot. Back bulkhead, sides removing carpets, boot removing floor. I sealed the 3rd brake light and am confident it's dry, no runs of water with lud open on the interior skin so to speak.
I was thinking the metal boot lid is so thin and cold overnight it creates coldness thus condensation, like warm meeting cold on house windows, moisture to droplets to condensation occurring.

Only reason I'm thinking this is, ive been putting a towel across the boot lid under the outdoor cover, it's dry inside the boot lid every time.
 
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Gatsoburner said:
All points in the boot are dry, no dampness in any corners or floor, I check it every time I open the boot. Back bulkhead, sides removing carpets, boot removing floor. I sealed the 3rd brake light and am confident it's dry, no runs of water with lud open on the interior skin so to speak.
I was thinking the metal boot lid is so thin and cold overnight it creates coldness thus condensation, like warm meeting cold on house windows, moisture to droplets to condensation occurring.
Click to expand...
Condensation can only occur when there is enough moisture in the air. To get condensation on the bootlid, the air within the boot needs to be excessively humid. You have got moisture in there somewhere. Doesn't need to be much..but there is too much, hence it condensing out onto the colder bootlid.
 
Hmm..I'm wondering if the rear light clusters are holding water, outer seals look poor ish, no water visible but I guess they could be damp.

I shall continue my quest, Feel like Aquman faffin about with water issues on the car.

Anyway, newbie winter cover on tonight, see what comes tomorrow 😊
 
Gatsoburner said:
I shall continue my quest, Feel like Aquman faffin about with water issues on the car.
Click to expand...
Welcome to the world of convertible ownership! I have had much newer convertibles than the Z3 and have had the same issues. Basically, the UK ain't the best place to own a convertible.
I had a £35k F33 BMW convertible with 2 gallons of water sloshing about inside the rear wings. You could hear it. I have had an E89 where the battery was almost floating.

My Z3 had gallons (and I mean gallons) of water inside it when I got it. Fried several very expensive pieces of electronics aswell.
 
We had an 07 A4 Convertible which was good until thr cam chain chewed itself up. 3k. Later it was back on the road.
Boot roof motor was the only other issue due to the electric motor brushes being dirty often causing a poor connection.
I'm sure once spring comes I'll get on with driving the car and enjoying ourselves.

MOT Monday which I'm pretty hopeful should be a straight pass. Done all the checks I can myself so fingers crossed. Garage quoted £250 for an undeseal which I'm tempted by, anyone else sealed theirs ?..
 
zroadster.org

Boot lid lining?

Afternoon you lovely Z lovers haha Just wondering if anyone has a boot lining or plastics on the inner of the boot lid? I'm getting a lot of condensation on the boot lid which is starting to get annoying as anything in the boot is getting damp. the carpet still feels dry just starting to...
zroadster.org zroadster.org
Old post here about fitting a liner to the boot lid, I put one in mine much the same as this one.
 
I’ve used Lanoguard. Self applied so you can have a good check of the condition of everything. Really easy to apply and, other than a sheepy smell, mess free.
Good luck with the MOT.
 
colb said:
zroadster.org

Boot lid lining?

Afternoon you lovely Z lovers haha Just wondering if anyone has a boot lining or plastics on the inner of the boot lid? I'm getting a lot of condensation on the boot lid which is starting to get annoying as anything in the boot is getting damp. the carpet still feels dry just starting to...
zroadster.org zroadster.org
Old post here about fitting a liner to the boot lid, I put one in mine much the same as this one.
Click to expand...

Ah great..cheers👌
 
ChrisD said:
I’ve used Lanoguard. Self applied so you can have a good check of the condition of everything. Really easy to apply and, other than a sheepy smell, mess free.
Good luck with the MOT.
Click to expand...

I'll have a look at that, keen to do something. Cheers 🍻
 
Check the left hand well, pull the carpet Back from by the rear light, there's a deep well there that houses an alarm module put your hand deep into it to check for water, it's a regular spot for water from a leaking aerial grommet if it's gotten in there's no way for it to get out.
 
Nodzed said:
Check the left hand well, pull the carpet Back from by the rear light, there's a deep well there that houses an alarm module put your hand deep into it to check for water, it's a regular spot for water from a leaking aerial grommet if it's gotten in there's no way for it to get out.
Click to expand...

Yes, had that one and solved it. New alarm module was my first job, never seen so much water sat in a car panel. Ruined the module but secured another and refitted. Decided to fit upside down just in case but its been dry since mid December
20251216_143800.webp
 
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