The store I work at is closing/liquidating. We have 6 gallons of RV coolant, quite cheap as a result. It says not to put in cars. It says that it is propylene glycol (vs ethylene glycol). I thought it would be easier to find out more, but I'm not seeing any literature on the internet for why it WOULDN'T work for cars. Only that several manufacturers experimented with it for its much lower toxicity, nothing about why it could be bad for a car. Can someone tell me more, then? Can I buy this propyelene rv/marine coolant and use it when I refill my coolant after doing the timing belt/water pump on my 1989 mazda 323? If not, why not? ...as an aside, there was another thread about Nissan coolant. Does my older sister need to use Nissan coolant for her 2010 Versa, and if so, why? ...and what's special about European blue coolants? Besides being blue, and having bittering agents. I got some free Volvo coolant that I've now run in my other 1990 ford wagon for 2yrs, no different I don't think. thanks!