Condensation on my gas tank?

For some reason I have to clean my windows every 2 or 3 days as a film fogs the windows, I thouhgt maybe from the trunk/boot? I checked the fear deck flaps are ok, but then I saw my fuel tank was covered with condensation! The car is in sw fl. And has just been sitting in the drive, any ideas this one has me stumped, I had the tank out to fix a few years back and painted it black but I don’t think that would cause a problem.

Got any wet carpets? Sounds like rain water leaking in somewhere.

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How is the coolant level - losing any coolant? A leaky heater core can fog the windows and deposit a film of coolant. Any coolant (sweet) odor after running the car with the engine up to temp?

Fixed the leak from the a/Condensation a d dried carpets out of car. Still wondering about the sweating gas tank

I will recheck the coolant level but no odor in the car.

Take all the carpets out of the boot for the tank condensation and check the rear foot wells to make sure there isn’t any dampness there.
I had a leak form the drivers side windscreen scuttle that was allowing water to get into the rear footwell. No idea how it was tracking back there but it was.

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That tank is 97 degrees how could it possibly sweat?

I suspect the tank with fuel in it cools to ambient temperature at night. Takes time to heat that 100 pounds of fuel up in the day. So the tank stays cooler than the inside of the car when the sun starts to heat it up. Any moisture in the carpets starts to evaporate when it gets heated up during the day. The water vapor in the air inside your car then finds the cool gas tank and condenses again. If you have the moisture ingress fixed maybe some better ventilation is needed to get it dried out better. Have you tried a little electric heater on the carpet to dry it out. Leave the windows open to get the humid heated air out of your car.

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I am going to try open trunk and windows for a few days, to dry things out? Air things out? I did notice a rust spot dead center under the rear window frame small but a possibility.

If you have externally visible rust you should be able to see evidence of water ingress (rust streak) inside the boot if that is indeed the source of the condensation. Pull the liners and spare tire and have a look with a bright light. If that appears to be the source you best, as Barney Fife would say, “Nip it in the bud” else it’s all downhill from here.

I forgot to mention it has a sunroof! Left the doors and windows open today and noticed some dripping late in the day from what I believe is the sunroof drain on the drivers side, have to find out how to be sure the back drains are clear and hoping that is the problem inside, the gas tank still has me perplexed.

Is there any sort of duckbill at the top of the rear sunroof drains or can I just shove something up there to be sure they are clear?

If leaving the trunk open to dry out and air out disable the trunk lamp. I do not think it turns off like the interior lamps after a period so could run your battery down.

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There should be drain holes at each corner of the sunroof chanel, strimmer line fed through should help to see if they are blocked, they exit at the rear of the front wheels and the front of the rears.

Actually they exit behind the rear wheels but I think I have them clear.