GSF condensation in rear light

[F.A.]

Noticed this is getting worse. Started just at the top but has  started to drip down the side as well and is happening on both sides. Lexus aren’t interested so I guess it’s two new lights. Disappointing again, I noticed that this is relatively common on the German marques, but looks like Lexus is no better. Has anyone else experienced this? 

[Jgtcracer]

10 minutes ago, F.A. said:

Noticed this is getting worse. Started just at the top but has  started to drip down the side as well and is happening on both sides. Lexus aren’t interested so I guess it’s two new lights. Disappointing again, I noticed that this is relatively common on the German marques, but looks like Lexus is no better. Has anyone else experienced this? 

When I was younger I would put lights in a cool oven to dry out and reseal.  May be worth looking on the YouTube to see if there are any guides as it’s going to be expensive!

[hockeyedwards]

That is annoying, I am really certain another owner had them replaced under warranty by Lexus, but name escapes me.

I would check every nook and cranny of the internet for a solution before new lights, that will be an expensive piece. Maybe the car that got broken on eBay would be a cheaper option?

[mrfunex]

Happens in my GSF and my Boxster too. Doesn’t happen in my wife’s NX300.

I wouldn’t worry.

[Linas.P]

I assume bad seal on the bulbs... 

[Spock66]

1 hour ago, Linas.P said:

I assume bad seal on the bulbs... 

I suspect light clusters can't be designed to be fully hermetically sealed.

Clearly it needs to be waterproof externally, but if it was fully sealed there would be large variations in internal pressure under different weather conditions.  So for example in full sun on a hot day temperature would likely be >50C which would create a large internal pressure (and it would probably at least crack if not explode) unless there was a vent somewhere. If there is a vent then moisture in the air will be present which may cause condensation under some conditions.

[Linas.P]

13 minutes ago, Spock66 said:

I suspect light clusters can't be designed to be fully hermetically sealed.

Clearly it needs to be waterproof externally, but if it was fully sealed there would be large variations in internal pressure under different weather conditions.  So for example in full sun on a hot day temperature would likely be >50C which would create a large internal pressure (and it would probably at least crack if not explode) unless there was a vent somewhere. If there is a vent then moisture in the air will be present which may cause condensation under some conditions.

Good theory... but I suspect internal volume of air is not great enough to create the differences in pressure we are talking about. On top of that dry air doesn't really change in volume that much, what has higher difference in volume is water, especially going between hard, liquid and gas form... so as long as they are hermetically sealed there should be no problem.  

To calculate gas volume we can use Charles' Law - and the difference between -50C and +50C would be about 44% for "ideal gas" (but ~78% of air is nitrogen which is quite close to ideal gas), so let's say 50% difference for the dry air. Meaning that if at 0C the air pressure in the taillight was equal to atmospheric pressure, then in +50C it would be 1.25ATM and in -50C 0.75ATM... So in conclusion - no 0.25ATM difference won't cause plastic cracking... BUT introduce some water and the results can be drastically different. 

[Duggie B]

Bet OP is glad he asked the question

[F.A.]

Thanks for the replies everyone. 
 

It seems to have cleared up for now but I will keep an eye on it. 
 

It maybe something I will just have to put up with ! 

[Ashrez]

On 2/7/2023 at 12:48 AM, hockeyedwards said:

That is annoying, I am really certain another owner had them replaced under warranty by Lexus, but name escapes me.

I would check every nook and cranny of the internet for a solution before new lights, that will be an expensive piece. Maybe the car that got broken on ebay would be a cheaper option?

Hahaa, that was me. I got mine replaced under warranty. Had to call and confirm with Lexus Corporate that condensation was covered and insisted a Lexus Dealer do the claims application.