[The-Traveler]

I've had my E90 sedan for a few years now and everything is mint on it, except the lower and upper vents stink of crayons when the heat is on. Not when the AC is on.

The middle vents don't, and I had the AC condenser or whatever the hell leaks in there replaced so it's clean as a whistle.

For whatever reason, there is something around the heater core near the bottom that stinks when heated. The closest I could find online is this F30 video showing the insulation around the firewall that can be changed.

Before I rip apart the dashboard, would love to have a game plan! Please help! It's been annoying for years now!

https://www.youtube.com/watch?v=Wojqg9nwaJA

[lowrydr310]

The crayon smell isn't too bad itself but on my 325 there's an additional smell of dirty/dusty rotting plastic.

I've cleaned my car many times trying to get rid of them both. I removed the lower dash trim, glovebox, and vent trim and left a high velocity fan blowing fresh air for half a day and that improved things quite a bit. I even did an ozone treatment and scent bomb and that also helped but didn't completely eliminate it.

I found the crayon smell was caused by that crumbling gray plastic, and spraying it directly with a liquid spray air freshener (non-aerosol) improved it quite a bit. Now I can't really smell that crayon smell at all.

I also learned that disgusting dusty rotten plastic smell is coming from the ebox and ebox duct. There's a fan and duct from the ebox through the firewall venting under the dash, and when that ebox cooling fan turns on it fills the area under my dash with that stinky smell where it just sits there trapped. I left my car parked in the garage for a week with the eboxnlid removed to air out then put a paper air freshener in my ebox and that helped for a while, but really just masked the nasty smell. I wish there was a way to ventilate that ebox better.

[mecheng77]

The crayon smell is typical on some German cars, it was really strong with my friends VW Jetta.

I don't notice it on my car but I've read it's due to the rust proofing they use on the metal.

[Smgs1992]

Its something in the glue they use on german cars. My vw and bmw both had that smell and if you google it youll find its very common

[The-Traveler]

Originally Posted by lowrydr310

The crayon smell isn't too bad itself but on my 325 there's an additional smell of dirty/dusty rotting plastic.

I've cleaned my car many times trying to get rid of them both. I removed the lower dash trim, glovebox, and vent trim and left a high velocity fan blowing fresh air for half a day and that improved things quite a bit. I even did an ozone treatment and scent bomb and that also helped but didn't completely eliminate it.

I found the crayon smell was caused by that crumbling gray plastic, and spraying it directly with a liquid spray air freshener (non-aerosol) improved it quite a bit. Now I can't really smell that crayon smell at all.

I also learned that disgusting dusty rotten plastic smell is coming from the ebox and ebox duct. There's a fan and duct from the ebox through the firewall venting under the dash, and when that ebox cooling fan turns on it fills the area under my dash with that stinky smell where it just sits there trapped. I left my car parked in the garage for a week with the eboxnlid removed to air out then put a paper air freshener in my ebox and that helped for a while, but really just masked the nasty smell. I wish there was a way to ventilate that ebox better.

What is an ebox, and where do I find it?!

[lowrydr310]

Originally Posted by The-Traveler

What is an ebox, and where do I find it?!

It's a white plastic box under the hood near the firewall on the passenger side, inside is the DME along with some other electronics, and a lot of wires going in and coming out. To access it, you'll need to remove the lower tray that holds the microfilter and remove the plastic cover, then slide three locking connectors on the lid of the ebox.
'
This video shows how:

(disregard the DME removal, you shouldn't need to do that, just pop the cover off and see if that's the source of some nasty smell)

[J. Dub]

Anyone have a fix for this?