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Fixing Foam Insulation Coming Out Of A/c Vents.

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There isn't a topic here that addresses what product to use when foam comes out of the vents. The 626 does not have a cabin filter. You can modify the HVAC system to accept one but that's a different topic. As your car gets older the filter media surrounding the vents will deteriorate to the point it becomes flaky, falls into the vent, and pushed through the system. When you try to hold it in your hand it will essentially turn into dust as at that point. The media itself is a fine threaded sponge material that when new is like a sponge but when old it's structural integrity is so weak it will disintegrate with the slightest touch.


Here's a closeup of the material.


So how to replace it and where to buy?

You can do an internet search for "Urethane Foam Tape". There are many suppliers of this product which change from year to year so there's no sense in linking to a specific product page as in the future it will likely not exist since it's a niche product. Companies like 3M do make similar tape but as a rubber seal however to my knowledge they do not offer tape with the specific foam required for usage in our application. The foam used in automotive A/C duct work and the filter media was chosen specifically for the application. The foam acts as a seal but due to the condensation buildup in the A/C vents the filter does not hold water vapor permanently otherwise mold will be created. Evaporation of water vapor through the seal where duct work connects to the vents is allowed up to a point. The thickness of the foam filter seal matters in that regard. It has to be thick enough to prevent all air from leaking into the dash instead of going through the vents but porous enough to allow water vapor (for mold prevention) to escape.


What NOT to buy:

You do not want the rubber sealed tape or something thick like this...


Air and water vapor must be able to escape from the foam tape itself. Something such as the above product will not allow that to happen and can be a source of mold in the future.

Most 626's from 1978-1997 have already experienced foam spitting through their vents. It's just about time for the 5th gen owners to have the same experience as the foam begins to break down from age. If you see foam spitting through your vent don't worry it's normal as the foam ages. It is fixable but you'll have to remove your A/C vents to get to it. Some vents are as simple as popping off with a screwdriver such as the one above the glovebox. Others such as the ones in the dash are part of the main dash bezel and the bezel has to be removed to gain access to the vent. In any event there are replacement products available online (I haven't seen anything compatible in local automotive parts stores). Simply perform an internet search for "Urethane Foam Tape" and you'll be supplied with plenty of results to choose from.

If or when you replace your insulation please post here what product you used and if possible a link to it for others to try out. As time goes on and with people contributing here we'll be able to pinpoint suitable replacements for every version of the 626. The thickness of the insulation will likely vary generation to generation so please speak up with your experience(s) in replacing your vent insulation.

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Firstly, can I say great write up! Thanks Devon.

Just want to clarify though:

The 626 does not have a cabin filter.

Not entirely true. Depends on which spec. For example, my 626 has a cabin filter. It was the US spec that never got one. And I'm not sure, but as far as I can tell, none of us with the cabin filter have had the foam problem.

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