Condensation in car possibly from LPG tank?

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lawler999
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Condensation in car possibly from LPG tank?

#1 Post by lawler999 » Thu Oct 15, 2020 7:07 pm

I am getting a lot of condensation in side my car now the weather has changed and was wondering if there is anything i can do to stop the LPG tank from sweating .
I have a lexus sc430 which has been brilliant in the 2 years i have owned it ,but now its a constant pain with all the condesation inside the car , i have a cylinder tank in the boot , and being a hard top convertible im guessing the moisture finds an easy path onto the rear glass and the rest of the car . Its nearly 20 years old so hasnt got all the modern heated screens , but is a pain this time of year.
Can the LPG tank be insulated to stop it getting so cold ?

Brian_H
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Re: Condensation in car possibly from LPG tank?

#2 Post by Brian_H » Thu Oct 15, 2020 7:22 pm

The tank gets cold because of the liquid being drawn off. I'm not sure insulating it would help, though maybe you could fashion some sort of drain from it to allow the gatherered water to escape? It won't be sweating as such, its more a case of its attracting the moisture already there because its colder than the rest of the car due to the rate your drawing it off at. Same way that a dehumidifier works.

A space heater running off a cylinder does the same - those get cold enough they can end up covered in a layer of frost, though its always damp with one of them running due to burning the propane generating water vapour. That shouldn't be an issue for you as the water produced would go out of the exhaust, not inside the car.

I'd have a good look around to see if water is getting in somewhere you can't see it straight away and see if you can do anything about it, Particually if you park under trees you can find leaves gather in places you don't see them and block drains up, Don't know your specific car, but under the windscreen where the wiper mechanism lives is a common place for that to happen.

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Re: Condensation in car possibly from LPG tank?

#3 Post by Gilbertd » Thu Oct 15, 2020 7:57 pm

A propane bottle temperature will only drop significantly if you are drawing a lot of vapour from it as it is evaporating in the tank. An LPG system in a car draws liquid from the tank so the same shouldn't happen. Have you actually seen condensation on the tank or are you just assuming that is where the damp is coming from? My experience with older convertibles is that they always leak and get damp inside which is why my partner bought a Mercedes SLK, roof down when you want it but a solid roof that doesn't leak when you don't. You only need a small leak somewhere for there to be enough damp air in there to cause it to mist up when parked.
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Brian_H
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Re: Condensation in car possibly from LPG tank?

#4 Post by Brian_H » Thu Oct 15, 2020 8:08 pm

Rear light clusters another place I've known to leak without being very noticable where its coming from, particually if they are the type with a foam gasket behind them.

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Re: Condensation in car possibly from LPG tank?

#5 Post by Pinger » Fri Oct 16, 2020 2:01 pm

Seals (doors, windows, etc) respond well to silicone. Halfords sell aerosols of it for the purpose.
I'd suggest you get on top of this ASAP before the damp permeates the electronics.

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Re: Condensation in car possibly from LPG tank?

#6 Post by LPGC » Sat Oct 17, 2020 7:47 pm

Tanks can get cold when drawing gas from them even though liquid gas is being drawn.. As liquid is drawn it creates more volume for vapour, so for vapour pressure to remain the same some of the liquid has to boil. Not a very pronounced cooling effect though, unless booting a very powerful vehicle with a relatively small capacity tank.

I agree with Gilbert and Bri's comments about leaks / convertibles. Also it's that time of year now when vehicles get condensation on the inside of windscreens etc. The Lexus will have AC, leaving it turned on will help keep the inside dehumidified ;-)
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Brian_H
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Re: Condensation in car possibly from LPG tank?

#7 Post by Brian_H » Sat Oct 17, 2020 7:56 pm

Just a thought on the AC front - If it does have it and it does work, could the condensation drain for it be blocked? That could account for an awful lot of moisture, when i've seen the results of it being blocked in someone elses car the carpet was saturated as a result of leaving it like that. In his case it was the result of a warranty fault with a faulty heater core originally which caused them to pull it apart and not get it back together correctly afterwards.

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Re: Condensation in car possibly from LPG tank?

#8 Post by Gilbertd » Sat Oct 17, 2020 8:17 pm

Good point, the AC on my Range Rover chucks so much condensation out of the drain, I've had people tell me I've got a leak when I've stopped for fuel.
96 Saab 900XS, AEB Leo, sold
93 Range Rover 4.2LSE, Lovato LovEco, sold
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lawler999
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Re: Condensation in car possibly from LPG tank?

#9 Post by lawler999 » Mon Oct 19, 2020 9:13 am

Thanks for the help , i have checked carpets they are nice and dry , i have been leaving the air con on all the time now and it has improved a hell of a lot , i dont think the AC drain is blocked as i get a nice puddle under the car when i have parked up afeter having the AC on .

Maybe its a combination of a the LPG tank , being an old convertible and NOT leaving the AC on all the time .
Will see how it goes over the next few weeks.

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