C63 w205 - white residue around coolant tank

[Matthewek]

Hi, few days ago I bought C63 AMG w205 sedan, year 2017 with 8000 miles on the clock, so very fresh.

When I bought it and inspected under the hood I did notice some white residue around coolant tank, but back then it did not bother me (maybe because I was overwhelmed by the car)

but now few days after purchasing it, it started bothering me, can it be something serious, like blown head gasket? (taking into consideration that it is 2017 model, with 8k miles, that would be strange for me)

Or it could be overfilled and tank cap released excess (I believe that's what cap does ?)

Any ideas would be appreciated, thanks.

 

[Ted]

Edit: wrong answer

 

[ChrisHGTV]

I would firstly clean it off and see if it returns. If it’s a dry residue it could be something as simple as dried spillage. What does the coolant look like inside, any sign of an oil film or anything or is the coolant nice and clean? Any residue inside the oil filler cap? Though you can often get some mayonnaise type goo in the oil filler cap if the car has done lots of short runs so that’s not always a good indicator. If you bought it from a dealer you could ask them to check, or take it along to an Indy for a quick check.

 

[Jobsworth]

Is it the engine coolant header tank or the chargecooler tank in the middle of the engine near the turbos? The chargecooler tank is very small and people often overfill it, because it looks nearly empty. Nearly empty is in fact correct. People put more in, thinking it’s low, but it just pushes the excess out, resulting in the white crust.