How to get rid of that crayon odor inside

[n1mrod]

Hi everybody.

This was published in the forum universe. Still, I thought you would find it interesting.

TDLR: The 'crayon' odor in vehicles of this vintage is caused by the foam padding found beneath the carpets. Removing the carpets, cleaning the foam below them, opening the windows, and using odor masks should get rid of the odor. Moderately challenging (you'll need access to outside space to lay the carpets out to dry and air, and it'll take the better part of a week to complete due to the several drying processes).

It's been approximately 5 months since I first got my 2009 S204 C180K. I really enjoy it, but the ancient, somewhat musty, "crayon-like" scent inside was driving me crazy. Not that a C-Class estate is particularly youthful manly, but I'd rather not be seen driving about in anything that reeks of senility. I had become used to it, but now that it bothered me every time I got into the vehicle, I realized I had to do something about it.

I did a lot of reading to try to find out where it was coming from, and what I found was a lot of hypotheses and disinformation, but no clear answer either.

My wife was gone for a week, so I decided to look into it myself.

The scent is coming from the foam padding/insulation below the floor carpets, and not the AC unit, the waxy material surrounding the center console, the oil burn-off from the engine, or the floor mats. While others have made this discovery as well, the truth is buried behind so much nonsense and wrong theory that I felt it was worth replying firmly and sharing what I did to get rid of it. There has been no recurrence of the odor in the two weeks after I treated and restored the carpets.

By really smelling and tearing things apart all over the inside, I was able to pinpoint the source of the odor to the foam. It seems sense that people would attribute the odor to wax or the carpets themselves, given how easily the odor spreads and sticks to neighboring surfaces. However, there can be no doubt about the origin once the carpeting in the driver's and passenger's feet are lifted and the foam is smelled. The fragrance is retained by the foam itself, not the adhesive that adheres it to the carpet's backing and seeps into the carpet fibers over time. While I imagine this foam is used throughout the vehicle, I found that the scent was concentrated in the footwells of the driver and front passenger and found that spraying only those areas was sufficient to get rid of the odor. I read online that some Thais had replaced their mattresses' foam with pieces of yoga mats, which sounded outrageous to me at the time. I've also seen repeat orders of the same carpet by the same customers who later complain that the fresh pieces have the same unpleasant odor.

Fortunately, both gaining access to the foam and removing the carpet flooring are simple tasks that need essentially the same steps.

A flat-head screwdriver and a wrench or ratchet with a 13mm socket are also required tools.
- Laundry detergent and dish soap
About a liter of white vinegar (the cleaning kind, not the dark thing you put on chips)
Scrubbing brush with bottle of cleaning solution.
About 1 kilogram of baking soda
- Juice of one lemon (optional)
- Any other odor-masking perfumes you'd like (I mixed Chemical Guy's New Car Smell and Leather aroma with a touch of Febreeze).

The vehicle may be driven without flooring throughout this cleaning procedure; the accelerator pedal just has to be reattached. However, driving with no cushioning beneath your foot is really an adjustment!

Process:

First, take off the floor mats and tilt the front seats all the way back.

The black plastic foot protectors at the base of the door must be pulled up next. These are attached through clips, so you should be able to unclip them and pull them up by hand. To free them, I initially pulled up on one side. Once the door is raised, you may seal it by pulling the fabric door seals up the front and around the bottom.

Third, take off the black plastic molding that surrounded the outside wall of the footwell. If the panel's clips were hidden behind the fabric seals, removing them would reveal them. To disengage the panel from the door frame, slide a tiny flat-head screwdriver under the clips and pry up on them to release the panel.

Fourth, the driver's side accelerator pedal must be removed (this is less of a challenge than it seems). You'll need to unplug a tiny electrical plug and remove two 13mm bolts (which I stashed in my cupholder for safekeeping). The wire connector is sometimes difficult to disconnect. The top clasp that holds it in place may be pushed down and taken out using a little flat-head screwdriver. It was difficult to see and position myself to reach at first, but once I did, it flowed out effortlessly. Take care not to break or otherwise damage the plastic piece that serves as a clip. The pedal may be readily removed after it has been detached. There is no need to take out any more pedals.

Take up the carpeting, step five. Initially, take the carpets' upper edges and pull them out of the rear of the footwells and around the sides. The carpet is only partially tucked away, and all that's needed to get it out is to remove the other pieces of plastic molding. After the perimeter has been cleared, the main section of carpet may be yanked up. It's a bit of a pain to do this since the foam is shaped to fit the metal floor, but it's not cemented down. It's simply a little cumbersome to get rid of, so please be patient.

Sixth, after both sets of carpeting have been removed. If you can, give the bare footwell a quick vacuum to get rid of the dust and debris that has settled there and then wash it down with some home spray surface cleaner to get rid of any lingering musty odors.

7/ Clean the area rugs and carpets. I used the shower head in my bathtub since I don't have a yard. After rinsing out the bulk of the dirt and dust, you should give both sides a thorough shampooing and scrubbing. I merely used regular liquid laundry detergent and a little dish soap; nothing fancy or specialized. Even though they look clean at first glance, you will watch the dirt and grime lift off as you use the cleaner. Be careful to clean the surface thoroughly (without ruining the foam) and work the soap deep into the foam on the back. The foam on mine had a few splits, but I was cautious not to widen them while washing them (the gaps can be gaffer taped up after they dry). After washing the carpets, squeeze out as much water as you can and lay them out in the sun with the foam side up. I would guess that you should keep them out of direct sunshine so that they don't bake (and the odor doesn't cure and grow worse), but that's just a guess. I have no idea whether it is possible or not. Fortunately, I could spread them out on a balcony that received some shade.

I sprayed the wet foam and carpets with white vinegar (to which I had also added some lemon juice) while they were still damp. White vinegar has been scientifically demonstrated to be an effective deodorizer. WARNING: This may leave a strong vinegar smell in the carpets after application, but it will dry and go along with any other odors. Similar to how alcoholic beverages evaporate throughout the cooking process. Scrub the vinegar into the carpets and the foam by spraying it from all angles. Flip the foam back over. The other side of the foam should then be liberally dusted with the baking soda. Have no fear. Apply it with your fingers and work it into all the nooks and crannies; I tried to upload a picture I took of this process, but the forum isn't allowing me.

9. Let it dry where it sits. Depending on the weather and temperature, at least overnight. Bicarbonate of soda acts as an odor sponge; the longer the odors are left, the more it soaks up.

10 Scoop up the bicarbonate of soda after it has dried to a satisfactory degree (it need not be completely dry at this point). When finished, a quick sniff test will show you how it's supposed to smell. My situation had improved, but the odor persisted in the denser foam sections, so I decided to repeat the vinegar/bicarb cycle and let it dry for another day.

11/ Once the non-carpeted side is dry, turn them over and treat it in the same way. On this side, the vinegar may be scrubbed in well to be effective.

12 - This time, give them plenty of time to air out. If you notice that certain parts of the object aren't drying off, try elevating them off the floor. That seems to quicken the process for me. When the bicarbonate of soda has dried, vacuum it up once again.

Take a second sniff. The improvement in the foam was noticeable; at this stage, I had to work to get the same scent.

14/ The next stage is to let nature take its course and air them out for a few days. Don't neglect this step, since it's crucial to ensuring that the carpets and foam dry completely. Putting wet carpeting back into your vehicle will just create a new, unpleasant odor. For more neutralization, I would sometimes sprinkle a small spray of white vinegar over the surface. The odor was almost undetectable even up close after two days of airing and further drying.

15/ This step is probably unnecessary, but I sprayed some odor masking/eliminating sprays on it just in case the scent came back. I don't believe any of these sprays are permanent, but even if they just reduce the musty odor by 5%, that's better than nothing. I combined Chemical Guy's New Car Scent and Leather Scent in the bottle for spraying (I don't think either is quite right; the new car smell is a little too chemically, and the leather scent is a little more like an old arm chair than new leather, but the combination seems to create a newer leather smell). I then sprayed in some Febreeze (which claims to effectively eradicate odors on a particle level) because, hey, why not. Since Febreeze has a strong odor, I just used a little quantity in the recipe so that it wouldn't be detectable by smell. I worked the scented spray into the foam well so that it would penetrate the material rather than simply sitting on top.

I waited another day to allow everything dry and to reduce the intensity of the spray's scent, which may be overwhelming right out of the container.

In the midst of this, I was also washing the floor mats, which had definitely soaked up part of the musty odor over time.

18/ Once everything was dry, I hoovered the carpets and foam one more time to remove any trace of bicarbonate of soda or dust, and then I put them back into the vehicle beside the floor mats.

19Once I got everything back in the car and put the finishing touches on, I sprayed them again with the custom fragrance blend and, for good measure, detonated a Meguiar's new car aroma odor eliminator bomb inside the vehicle. This last step was probably unnecessary since the bomb didn't have a really pleasant aroma. The perfume is too sweet and vanilla-like, not like a brand-new automobile. I found that leaving the windows cracked and wiping down the seat vinyl and inside plastics with an interior trim finisher helped to significantly reduce the intensity of the odor.

Done.

As I said before, it has been two weeks after treatment, and the odor seems to be gone. But my thinking from the beginning was that even if I could cut it in half, it would be a huge improvement and may just need minimal maintenance to maintain. So far, though, I'd say the odor has been eliminated entirely.

There is probably more foam that hasn't been treated or cleaned in other areas of the vehicle; I'm presuming there's some in the back passenger footwell and I know there's some beneath the front seats but I didn't want to remove them. You may consider treating these places as well if you wanted to perform a very thorough job.

I'll let the group know if I smell anything again, but things seem to be OK at the moment.

Please let me know if you find a better solution to this problem.

[sighn34]

The unpleasant odor you describe comes from the manufacturing and is impossible to eradicate.
Plastic and rubber parts in any vehicle will give off a distinct odor.
Have you ever compared the scent of a brand-new automobile to that of your own vehicle?
If so, how?

Nothing is odor-free after a long day at work, not even the automobiles.

have it to a detailer and ask them to have a look around; they'll know what to do if they find anything amiss.
I'd have headaches and a sore jaw from pretending to chew bubblegum all the time, but Autosmart has a fragrance machine with various aromas, and I enjoy the bubblegum flavor.

[n1mrod]

The unpleasant odor you describe comes from the manufacturing and is impossible to eradicate.
Plastic and rubber parts in any vehicle will give off a distinct odor.
Have you ever compared the scent of a brand-new automobile to that of your own vehicle?
If so, how?

Nothing is odor-free after a long day at work, not even the automobiles.

have it to a detailer and ask them to have a look around; they'll know what to do if they find anything amiss.
I'd have headaches and a sore jaw from pretending to chew bubblegum all the time, but Autosmart has a fragrance machine with various aromas, and I enjoy the bubblegum flavor.

[Bluewhaleeee]

I read all you wrote.

My vehicle is somewhat older than yours, and I haven't taken any special measures to eliminate odors.
I have used the Autosmart odor machine once, but with the neutral cartridge thus the room didn't have any unpleasant odors.

A musty odor has been emanating from my air conditioning vents, but I have some AC cleaning solvent to get rid of it.
This is the norm for vintage automobiles and MB.

Even though the foam in my carpets is becoming old, they don't have that musty odor.
MB vehicles varied in the technologies they utilised.

The smartest thing to do is to get advice from a professional.

[n1mrod]

To be quite honest, I have no idea what to say to you or why you insist on disagreeing with me.

You're disagreeing with a statement made regarding an automobile you confess you don't own, an issue you've never encountered, and a solution procedure you've never attempted.

I have tried and tested the aforementioned procedure, as I detailed in the first article. I was able to get rid of the "problem" crayon-like odor (widely reported on the W204) that has plagued my vehicle. So there's no need for me to see a professional for guidance.
I'm sharing this solution with the community because it's a cost-effective alternative to taking the car to a professional detailer (which, I should add, many other W204 owners have done in the past, spending hundreds on and still not solving due to it being misdiagnosed, even by professionals) and because it only requires a few common household items and a little bit of effort.

It's up to you whether or not to accept my word for it.

However, if you have any concerns about the procedure I followed, I'd be delighted to answer them. The odor hasn't returned after many weeks.

(For what it's worth, the Autosmart odour machine probably won't work on these 'factory' chemical scents since it, like other ozone machines, is primarily intended to eliminate odors based on bacteria, such as pet smells, smoke smells, and food smells. And that scent, even if designed to have no discernible aroma, is still a covering agent.

[STAR89colin]

I appreciate the lengths you went to in order to get rid of that odor. I have no idea what a "crayon" scent is like, but I do know that my husband and I once purchased an already smoked-in SLK. I was incredibly disappointed that we had missed it, especially as a hypocrite ex-smoker who despises entering inside any vehicle that smelled of smoke (they had the top down, of course, when we saw it). In order to clean, de-odorize, and wash the inside, I had to remove as much of the trim and headliner as possible.

after my best efforts, and after using two applications of a chemical 'air vidox' solution that left the vehicle smelling a little like a swimming pool, the smoky odor persisted. I had to keep the roof open whenever possible and continually cleaning it. Even after four years of ownership, I sometimes caught a whiff of the odor in the car, so I can see the desire to eradicate offensive odors from a vehicle. However, I don't see why anybody would dispute over it; as a relative newcomer to this forum, I've seen a few instances were posters would be a little 'blunt' on here, but usually they have been pretty pleasant, so I'm sure other owners would be grateful for your post.

[sighn34]

If Mercedes-Benz's use of odorous foam or adhesive in the design of the W204 was a mistake, the company would have been wise to issue recalls.
Have there been any recalls?

All that counts is that you had your automobile repaired and it doesn't smell anymore.
You performed well on a task that MB really should have handled from the start.

[KARlosfuentes]

Excellently intriguing. I just got rid of my 2009 CLK, but I remember that precise odor well; it wasn't quite as strong in our 2003 model, but the car is long gone.

After picking up a friend in it, she remarked to me, "I really love your car, why does it smell like crayons though?" So I contacted my wife and asked her about the strange odor. That sums it up perfectly! I had no idea what it was until she said crayons, and then I did. Ha. It wasn't horrible, and I think I had gotten accustomed to it by this point, but knowing why it happened is always helpful. Some of my acquaintances who went through the same C&E years as me said, "It has that Mercedes smell." This suggests that all the same materials were employed.
I can attest that neither our S202 nor our W166 had the musty odor that pervaded the CLKs; however, these cars are older and constructed from different materials.

Please keep me updated.

[dontito]

An traditional method involves setting out a Spanish onion on a saucer in the trunk of a vehicle.

[KARlosfuentes]

Crayons have a more pleasant aroma to me. I'm sure there's a scientific reason for how something with such a powerful odor can take on the scents of other things, but it's still an amazing phenomenon.