My friend drank a full glass of pure ethylene glycol and despite not being found for 3 days, she did survive. However, she is now disabled. She has kidney failure, which means she has to self catheterise, she struggles with extreme tiredness and problems with mobility, she needs crutches to get around, she has been left with neurological issues such as vertigo. At the time she was found, she had gone blind and she needed to be resuscitated. She can't take a lot of medications now, even psych ones that might help her feel better in herself, and she has to have regular blood tests and faces more rounds of dialysis.
This method was actually my plan, though she didn't know that, but now I've seen what's happened to her, it makes me more wary in case I did survive and I'm left with a bunch more shit to deal with.