CLK123

I recently bought a 2009 Mercedes Benz CLK 350 coupe. It was in excellent condition, except for a strong odor inside the car. I thought it was from an oil leak, but it was much more than that.

After an internet search, I determined the source of the problem was the padding under the carpet. I had the carpet removed. It made no difference, except it removed the odors that were already soaked into the carpet. The carpet padding was not the odor source in my case.

There was formaldehyde–like smell in the car which was from mold in the A/C system. This is a car with a fan that does not run after the car is shut off to dry the A/C evaporator. Its design is prone to growing mold. Later designs continue to run the fan after the car is shut off to dry the evaporator.

Removing the mold was a challenging repair. I used BG Frigi-Fresh and Frigi-Clean as well as ozone, chlorine dioxide and DrivePur Shok administered directly into the cabin air intake under the hood. Eventually, the mold was eliminated.

The car had been taken to a non-Mercedes shop for an oil change before it was sold. A tablespoon of oil had been spilled onto the cover under the engine. As the engine warmed, the oil vapor was pulled into the cabin. After power washing the engine area and changing the cabin air filter, this problem was eliminated.

However, even after a thorough cleaning of the interior, an odor of burned crayon remained. I went to a few Mercedes dealers and finally found one where the shop manager had owned the same car. He said the odor was from rust preventative “body wax” applied to welds on the frame of the car. He said there was no way to remove the odor. He had tried everything himself and had no success.

This is where I gave up. The odor is so strong that after two hours in the car I have a sore throat. From my research, it seems there are some other wax paper-like materials used in German cars with this odor as well. There could be multiple contributors to the problem.

I am posting this note for comments – and as a source of information for anyone who might consider purchasing or repairing one of these cars. (The CLK, SLK and SL models all have this problem in varying degrees. Convertibles have it worse because there are more welds in that design.)


Keywords:
Burnt crayon burned crayon

mercedesbenzs55

Seems like you bought a heavily flooded car. In which case you not get rid of it. The smell will not go away no matter what you try. Its in the seat foam, leather, everything.

PM me your VIN and I can run a free autocheck to see if that's the case. From what I understand there is no way to fully get that smell out of your car.

Does the smell get worse when the weather is hot or you blast the heat in your car?

eteller

I have a 2009 CLK 350 that I bought last August. It had that same odor, even my eight year old said it smelled like crayons. Since the odor has either dissapated or we don't notice it anymore, but I think it's dissapated as I do not notice it after getting in the car after a few days. I do drive with the windows down quite a bit so that may have helped.

CLK123

It sounds like your (eteller) crayon odor is less than mine. After 15 minutes in the car, I need to open a window.

I am putting the carpet back in this week. That might help. The odor seems to be strongest around the rocker panels.

eteller

After I got my car I searched the issue and yes it's does seem to vary in intensity. One Chinese owner reported some adverse effects from the odor. For me it was not really a big deal just different than the more organic horsehair (in the seats) and leather smell of my older Merc's and BMW's. Good luck with the issue. If you have a garage I'd certainly be leaving the windows down.

TSchuettinger

Most German cars if not all german cars get a crayon-esque smell when the "new car smell" goes away. I wouldn't say the smell is exactly crayons but imagine a crayon smell mixed with the smell of a building built in the 1980s that in really good condition but hasn't been renovated since. A somewhat musty and satisfying smell. Kind of like loving the smell of old books.

CLK123

I don't mind the odor itself, but in my car it's very strong. If it was a minor smell it would be fine. As is, it's overpowering.

MacClan64

I bought a 2008CLK 350 Cabrio last summer, which has been a great car with one exception... a mysterious scent.
I'd read a few feeds on what people are labelling a " crayon burning" smell.
This would describe the smell, however, I have also noticed an "eye discomfort", almost like what you'd get from campfire smoke.
I guess my question is two fold. Is there anyone with a similar situation re smell and reaction. As well and if so, how can you get rid of it ?

CLK123

The burned crayon and something like the "eye discomfort" you describe are there with my 2009 CLK350. I am still fighting the battle. It seems that everything I do makes it a little better, but it's not gone. I believe I have more than one problem. My current theory is that it's a little residual mold from the A/C system combined with the body wax crayon odor. Last weekend I put Kanberra Gel Natural Air Purifier in the car. We'll see how much it helps...

MacClan64

Thanks CLK 123,
I really don't mind the smell (if it wasn't an option otherwise), however, the whole reason for buying the 4 seater was to take the family for the proverbial Sunday drive, otherwise I would have loved to have gotten the SL550. My wife's acute sense of smell is to blame hear.
I'll wait to hear back re your test with the Kanberra Gel
Thanks

CLK123

Here are my suggestions:

Do not use ozone or use it sparingly. I found it mostly ineffective and it can cause harm.

Chlorine dioxide was effective. I would try this first.

Remove the cabin air filter under the hood just over the battery. Place a source of chlorine dioxide on top of the battery with a tent made from taped up cardboard pieces so the chlorine gas will be directed into the cabin air intake. With windows up, run the car with the fan on high to pull the chlorine into the cabin. Run the A/C system so it directs the gas over all vent surfaces.

For the chlorine dioxide source I used the “Odor Tablet” from SuperiorRestoration dot com. Be careful. If you spill this liquid it will bleach the color where it’s spilled. The chlorine odor dissipates in a few hours with the doors/windows open.

If any odor remains, try Kanberra Gel. It may be the best thing to remove odor from the interior, but it won’t get deep enough into the A/C system to fix that problem.

I found the crayon body wax odor was removed best by Organic Hogwash, available on Amazon. I have a mix of odors from several sources: mold in A/C, crayon odor from body wax and probably some other things as well.

Good luck!

MacClan64

Thanks CLK123,
I've just ordered the tabs and will make the tent as suggested.
I'm getting firmiliar with Chlorine Dioxide... pretty awesome sounding accolades, provided they work as they claim. Stay tuned and thanks once again.
Regards

Markis

Are you guys serious ? If you get in almost any mid 00's mercedes you will get this smell. At least i have. I thought it was the leather mercedes use. I happen to like it and appreciate it...

ps. i hope were talking about the same smell

mercedesbenzs55

I thought it was a Mercedes exclusive car smell. It's smells of fine word and leather.

TSchuettinger

I've smelled the smell in Volkswagen, BMW, Audi, Porsche, Volvo, Mini. It's not unusual and the smell goes back many many years. I like it though.