Do you still have a copy of the TSB please as our local dealer is saying it’s sweat. We have stains on back seats that are very rarely used and on the passenger seat but not the drivers. The dealer we bought it from thought it may be too much Gardex.
Hi, most definitely the glue under the alcantara cloth. It’s a known issue. Mercedes have replaced hundreds of interiors. He’s being economical with the truth, if he says there’s no other reports. My 2014 C coupe had the same issue. Dealers had the valeting done twice to try & cure the problem to no avail. Mercedes Grangemouth changed the seat covers. They took photos first & sent them to Mercedes & they agreed to replace the covers. Had to wait 3 months for replacements as there was a shortage due to the issue. They had the car for 2 days to do the job. Never had an issue since. Keep pressing the issue & don’t be fobbed off. Cheers, & good luck.