# A really stupid enginge/anti-freeze question (probably) **URL:** \ **Category:** Factual Questions\ **Created:** [July 12, 2001, 3:31am UTC](https://boards.straightdope.com/t/a-really-stupid-enginge-anti-freeze-question-probably/72177 "2001-07-12T03:31:39Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![chique](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@chique](https://boards.straightdope.com/u/chique)\ **Post date:** [July 12, 2001, 3:31am UTC](https://boards.straightdope.com/t/a-really-stupid-enginge-anti-freeze-question-probably/72177/1 "2001-07-12T03:31:39Z")
One is supposed to fill a radiator with a 50-50 mix, anti-freeze and water. Anti-freeze, if I understand this correctly, is supposed to keep the engine cooler in summer and warmer in winter. If that’s the case … wouldn’t it be better to put straight anti-freeze in? No? Why not? ---
**Author:** ![Chas.E](https://avatars.discourse-cdn.com/v4/letter/c/e99b99/32.png) [@Chas.E](https://boards.straightdope.com/u/Chas.E)\ **Post date:** [July 12, 2001, 3:44am UTC](https://boards.straightdope.com/t/a-really-stupid-enginge-anti-freeze-question-probably/72177/2 "2001-07-12T03:44:42Z")
The answer: consult your owner’s manual for proper antifreeze specifications. I have an old '65 cuda and it needs a 50:50 solution, I went too heavy on the antifreeze once and it ate right through the water pump. But those were the days when you were always boiling over and adding water at the gas station. These days, you can’t even find a gas station with a water hose. AFAIK, modern engines are designed to run on 100% antifreeze. Or at least, that’s how my '96 Toyota works. ---
**Author:** ![Booker57](https://avatars.discourse-cdn.com/v4/letter/b/b9e5f3/32.png) [@Booker57](https://boards.straightdope.com/u/Booker57)\ **Post date:** [July 12, 2001, 11:37am UTC](https://boards.straightdope.com/t/a-really-stupid-enginge-anti-freeze-question-probably/72177/3 "2001-07-12T11:37:43Z")
Anti-freeze/coolant mix is important. Pure in-the-jug AF will freeze at about 11 degrees below zero F. Mixed with water in a fifty- fifty mix it will protect downto -34F. Pure AF is also thicker than water and will not allow proper heat transfer. If it matters I was a NIASE certifed mechanic. I let it lapse. ---
**Author:** ![Una\_Persson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/una_persson/32/346_2.png) [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)\ **Post date:** [July 12, 2001, 12:37pm UTC](https://boards.straightdope.com/t/a-really-stupid-enginge-anti-freeze-question-probably/72177/4 "2001-07-12T12:37:06Z")
> [@](#): > > \*Originally posted by Chas.E \* > \*\*AFAIK, modern engines are designed to run on 100% antifreeze. Or at least, that’s how my '96 Toyota works. \*\* Which model? A call to my Toyota dealer says they know of no model that is supposed to be doing that - especially since the important _mixture_ of the two is best on both the cold and the hot sides of the scale…? I know of **no** “modern engines” that are supposed to be running on 100% antifreeze. And there is also: > [@](#): > > The freezing point of most liquids can be lowered by adding another substance. This fact is the basis for using antifreeze in automobile radiators during the winter. Antifreeze contains ethylene glycol, which has a freezing point of -13 °C. A mixture of equal parts of ethylene glycol and of water freezes at about -37 °C. These guys have a simple explanation, without getting into the chemistry involved. > **[Car News, Blogs & Analysis | Cars.com](https://www.cars.com/news/)** > > Browse up-to-the-minute automotive news and analysis, including expert reviews of the latest cars on the market, at Cars.com. ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [July 12, 2001, 1:53pm UTC](https://boards.straightdope.com/t/a-really-stupid-enginge-anti-freeze-question-probably/72177/5 "2001-07-12T13:53:51Z")
Water has better cooling capacity than ethylene glycol. As the Cartalk page says, the 50-50 mix makes a good rule of thumb. ---
**Author:** ![chique](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@chique](https://boards.straightdope.com/u/chique)\ **Post date:** [July 12, 2001, 3:18pm UTC](https://boards.straightdope.com/t/a-really-stupid-enginge-anti-freeze-question-probably/72177/6 "2001-07-12T15:18:51Z")
I should have known to check with Ray and Tom … Thanks for the link and info 🙂