martinos1 - When I had this, I called the master who fixed the problem. It is better to turn to professionals and do not climb yourself.

olominol - Contact the professionals. It could be a gas leak and cause serious consequences.

fenix33 - There was a smell of rotten eggs from my air conditioner and my family did not like it very much and I had to look for ways to solve the problem. I found an excellent instruction https://www.fortador-usa.com/blog/how-to-remove-smell-from-air-conditioner-at-home to remove rotten egg smell from ac. I advise you to pay attention to this material because it contains a lot of useful information on this issue.