I filled the gas tank to full & gas smell from inside car. Took car to local mechanic & replaced the o-ring on the gas tank under rear passenger seat. Driver side was not leaking. Filled up gas tank with the seat & gas plate off under the seat & noticed at 3/4 full gas started to seep again and same leak. Took it to Mercedes dealership. They looked & no recall on the gas tank. They indicated that a new gas tank will fix the problem for certain , but if they need to look at can finding the problem, it will be hours of labor & might end up being the gas tank anyway. Reading chats on the MB Forum & noticed an extended warranty on the gas tank for up to 15 years on earlier E class models with the same problem. Also read online that might be fuel sender pump and at 3/4 gas leaked, just like my issue. Contacted MB Corporate support & they indicated no issues or recall for such a matter on my make/model. Looking for someone with some experience if they have encountered this issue for this make/model & after 2012 models of the CLS? Help much appreciated.

Hello!

Welcome to MBWorld!

Your best bet for technical answers is the forum that best matches your chassis. I'm sorry, but I'm not sure which forum is closest to your CLS year but will look up tonight. Good luck!

Bob