Rear passenger side tail light fogs up - normal?
 

I was involved in a rear end collision (I was hit). The tail light was replaced but it's still fogging up. Is this normal because that tail light has the key hole or do you guys think something else is wrong? I had the entire tail light assembly replaced ($800).

Thx!

Mine (series 1) was also always fogging since new (without accident); I tried the new improved type of gaskets and payed a lot attention to a precise installation etc. still fogging........
Many other owners have the same problem and also always on the passenger side.........I now assume that this is a common production (sealing) failure of the subsupplier of the taillight and only for the passengers side one.
At last I submerged it in a bath; light bulb openings at the lowest point.
There was a small leak (tiny air bubbles escaped) between the clear plastic- and the black plastic halves {both (to be) "sealed/glued" together} at the upper part of the light assembly (in mounted situation). Rain water could enter constantly there.
There is some common slot/free space between these halves where silicone kit can be applied almost all around the tail light. At first this space should be cleaned in advance.
I rubbed clear silicone kit in it around the whole common sealing joint of both halves.
I did NOT inject it with the commonly used nozzle of the silicone cartridge pistol since in that situation you can not fill the common space sufficiently and will not achieve a complete uninterrupted sealing without enclosed air bubbles.
Apply the clear silicone kit in a "rich" manner time after time on your middle finger and rub/press it (in a 45 degr. angle versus the sealing joint of both tail light halves) into their common joint. You go all around the taillight paying good attention not to enclose trapped air......it takes some time but it is progressing surprisingly well. It is just like a wave of kit that you are driving forward around the joint.
Remove/clean the overdosis of silicone kit with terpentine and finally rinse the inner side of the tail light with distilled water in order to prevent limescale from the clear bathwater. Dry it at a moderate temperature with a hair dryer or give it a sunbath.
There is no specific expertise needed for this kind of repair; everybody can do it.
This worked perfectly for me.......never more any fog in my taillight.

Success and best regards, Ruud

The most common problem ever in the history of RX-8's. Search.

Well, the drivers side tail light started to fog up on me today after it was raining for hours. I emailed the body shop and am going to press this as an issue due to that accident. It'll have to be fixed as a supplement. I can't remember it doing this before the accident. I'm sure something is bent even if by only 1 mm it's enough to break the seal.

They'll have to apply sealant or something. Just replacing the tail light assembly isn't enough. They tried replacing the passengers side tail light assembly ($840) and that only improved it a little.

So now both are fogging up. -_-

I told them if they can't fix it in a couple of hours they'll need to schedule a rental car and file a supplement.

The other person was at fault so it's not like it'll cost me anything.

I had nearly the identical thing happen to me. The passenger's side rear panel got scraped and required repainting. When I got the car back the tail light on that side started fogging up. I took it back and was told it was likely due to the gasket on the back of the lamp not sealing when it was re-installed. They replaced it with a new one and I haven't had the problem since.

New Improved Material 2004 2008 Mazda RX 8 Taillight Gasket Gaskets Set Pair | eBay

Mazda F18951153A Genuine Tail Lamp Gasket | eBay

Mazda F18951163A Genuine Tail Lamp Gasket | eBay

One is for 04-08 the other is 09 and up. problem solved

Not really... Because he was in a rear end collision, it's very possible that the reason the tail light isn't sealing, has nothing to do with the gaskets. Especially since the light was replaced. Perhaps the metal is bent, not allowing the gasket to seal.

Definitely take it back to the repair facility. It's on them to fix it.

Super common problem, do not drill holes or any stupid shit like that. Dry out the taillights (take it out and make sure you just run hot air through it to get the stored moisture out.

I found just buying some weather stripping and following the gasket where it touches the metal (you will easily be able to tell when you take them off), you will be fine from then on out.