C300h w205 2016 Electrical fire in boot

[NacNac]

Hello,

I would like to share what I have just experienced and to find out if others had similar issues.
Yesterday morning I went in the boot to take the plastic crate and I was horrified by what I have found.
after I discovered this and try to figure out if the process was still ongoing or not. Everything was cold not smoke etc..., I put everything in place to film this video to contact Mercedes. The car is with them right now but I do not trust them and therefore I am doing research on the internet to find out if similar issues occurred.
I drove the car the night before for about 15min and did not smell anything or noticed. I have no idea if this has been a very slow process or quick. The only thing I know is that the last time I lifted the board was about 5 weeks ago and I had not noticed anything. It does not mean that the process had not started from underneath but did not make it through the flexible cover and therefore was not noticeable by just lifting the board.
Here is the video (no audio)

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

Thank you very much for any info.

 

[NacNac]

Hello,

I would like to share what I have just experienced and to find out if others had similar issues.
Yesterday morning I went in the boot to take the plastic crate and I was horrified by what I have found.
after I discovered this and try to figure out if the process was still ongoing or not. Everything was cold not smoke etc..., I put everything in place to film this video to contact Mercedes. The car is with them right now but I do not trust them and therefore I am doing research on the internet to find out if similar issues occurred.
I drove the car the night before for about 15min and did not smell anything or noticed. I have no idea if this has been a very slow process or quick. The only thing I know is that the last time I lifted the board was about 5 weeks ago and I had not noticed anything. It does not mean that the process had not started from underneath but did not make it through the flexible cover and therefore was not noticeable by just lifting the board.
Here is the video

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

Thank you very much for any info.

I did not mention it but the car has not being used by anybody else.

 

[KillerHERTZ]

Looks like an acid burn rather than a fire.

 

[NacNac]

Looks like an acid burn rather than a fire.

Thanks KillerHERTZ for your quick response.

Something hot or something that slowly consumed. As for acid, where would it come from? I can't even be something I could have put in the boot. 1) I have a heavy-duty mat (not shown in the video) to protect the carpet and it would have had to go through the board which as seen in the video the carpet is fine..
Where would the acid come from? This is not even near the battery.

I first thought, the electric cable became very hot and ignited something that started to consume the surrounding and make its way, thus me using the word fire.

I do hope to find the root cause. The car is currently at Mercedes but I like to have different opinions when possible. Cheers

 

[wongl]

I have the same model and year, so keen to find out what the root cause is.

 

[Deleted member 113659]

I have the same model and year, so keen to find out what the root cause is.

Me too.

 

[grober]

Looks like an acid burn rather than a fire.

AGREED Looks very like corrosive liquid damage- what was the last rectagular item you removed?

 

[Connoisseur]

AGREED Looks very like corrosive liquid damage- what was the last rectagular item you removed?

Compressor for the Tyrefit system I think...

 

[Mikesmith29]

You are correct it was the compressor.

The cable you looked at is the main earth from the battery.

 

[poormansporsche]

Nasty. I do hope you get an answer.

But it does look like someone has got one of Ellen Ripley's bad guys in your boot !!!!

 

[grober]

There probably lies the problem - the tyrefit liquid is likely to contain a solvent to keep the rubber liquid and if this was to leak out it might attack the surrounding plastic???? anyone like to check their hazard label [ the one with the large X on it] to see what it contains?
from a bike forum
Stan's is natural latex, Bontrager TLR is an example of synthetic. And it is ammonium hydroxide, NOT ammonia which is a gas. NH4OH is a cheap OLD SCHOOL pH adjuster but most coatings and sealant guys use secondary or tertiary amines in modern formulas to aid in stability and corrosion protection. AMP 95 is the industry standard for the better products. Maybe Stan's should give me a call if they really are using NH4OH? FWIW synthetic latex systems ALSO use pH adjusters in most formulas, depending on the polymer so it is definitely NOT something unique to natural latex systems.

 

[Petrol Pete]

How thick is the 'heavy duty mat' that was protecting your boot space , and was it supplied by MB ? If not be prepared for MB to come back at you and say it was your fault for putting a carpet on top of the load floor.

Remember NOTHING is ever their fault.....

 

[grober]

According to MERCEDES the tyrefit liquid sealant bottle should be replaced every 4 years!

C-Class - Interactive Owner's Manual

moba.i.daimler.com

 

[Fastcar155]

According to MERCEDES the tyrefit liquid sealant bottle should be replaced every 4 years!

C-Class - Interactive Owner's Manual

moba.i.daimler.com

Hi , well if that is the case surely Mercedes dealers should high light the service life of the sealant bottle.

However , why was the bottle not supplied in a separate box to catch fluid leak ?

 

[markjay]

The tirefit liquid bottle seems to be further away from the affected area, and contained in a plastic bag - did you check if it was actually leaking? And, has the compressor been used recently - could it have some liquid residue in it?

Failing that, does the main earth cable get warm (or hot) when the car is running? Could it have heated-up sufficiently to start a small fire?

 

[markjay]

BTW, it's an irritant, apparently, but there's no suggestion that it's corrosive (and no warning label, either):

Mercedes-Benz

 

[Trickythemerc]

If that has been caused by any sort of fire, there would have been smoke and a pretty acrid smell at the very least. Looks pretty scary though.

 

[Petrol Pete]

Am I missing something ? Where in the OP's video is leaking tyre sealant introduced into the mix here ? The split second when the zip bag was opened ? just askin' ?

 

[Ted]

The most likely thing to cause that imho is a bad connection where that main earth cable bolts to the body.
It only takes a very small volt drop - say 1 volt - at a nominal 300 amp cranking current to produce 150 watts of heat.
That would explain heat damage around the connection, but not the amount of damage I can see as the car only cranks for a few seconds.
Also possibly if those cars have a high output alternator and for some reason the charge current is going for a long time.
Both scenarios are unlikely, but there you are.
My diagnosis is a poor connection where the earth cable is bolted to the chassis.

 

[grober]

The tirefit liquid bottle seems to be further away from the affected area, and contained in a plastic bag - did you check if it was actually leaking? And, has the compressor been used recently - could it have some liquid residue in it?

Failing that, does the main earth cable get warm (or hot) when the car is running? Could it have heated-up sufficiently to start a small fire?

I suggested that the tyre fit bottle was a possible candidate because of its location and the nature of the damage. It may be that with the age of the container and its contents which may have broken down with time that it leaked corrosive vapour despite its enclosure in a plastic bag. As usual without hands-on examination of said bottle it's impossible to say at a distance. The overheating earth wire is another plausible explanation but I would have expected more localised damage on the cable itself. Such damage as seen might be caused by a small fire or smouldering for a long period. Perhaps the reason it wasn't worse was it was self extinguishing due to lack of oxygen in the boot otherwise the entire car might've gone up in flames! Let's hope the OP comes back to us with Mercedes explanation.