I was going to change the coolant from 70/30 prestone lowtox/distilled water to 100% lowtox for better freeze protection for the winter. After some reading I find out that it contains silicates. After more reading it looks like silicates are not good for impellers and seals. Here is the post from 2004 talking about silicates in lowtox: Quote: Does the prestone low tox have the silicates or is that not a part of the PG mix? I went on-line and asked the fine folks at Prestone if thier Low Tox product contained silicates. It took a few days, but they finally sent me an e-mail back: Hello Mr. Attack: Thank you for your inquiry. To answer your question, Yes. Prestone Low Tox Antifreeze Coolant does contain silicates. If you need additional information please let us know. Prestone Re: Another coolant question JackAttack, Thanks for the follow up. I was going to go buy some of the Low Tox just to save a few bucks over the bike specific stuff especially if the extra cost was due to marketing hype. Now I'm not so sure Re: Another coolant question After I recieved the first reply, I asked them another question: Does Prestone make a propylene glycol based coolant that does not contain silicates? Next day, I recieved an e-mail from them saying: Hello Mr. Attack: Thank you for your inquiry and your interest in our products. To answer your question our Prestone Low Tox contains silicates. Unfortunately we do not have a propylene glycol based coolant that does not contain silicates. Prestone This is the link to that post: http://www.thumpertalk.com/forum/showthread.php?t=165936&highlight=coolant It looks like amsoil sells a low silicate propylene glycol coolant. The question is how much silicate is safe to use in the coolant. If the answer is none then does anyone know of any propylene glycol coolant that is silicate free besides engine ice?