Who Wants a Warm Cup of Prestone®?

If you've worked around trucks or cars long enough, chances are you've had an occasion to re-use antifreeze. I'm not talking about doing a flush & fill with 100,000 mile coolant. That's cheapskate stuff. This is for those occasions where you have to replace a thermostat or leaky radiator hose six months after you shelled out good money for new antifreeze. Nobody wants to dump glycol-based nastiness down the drain, that's illegal. And if you're working for a living, you really don't want to drop another $30 for something you just replaced recently. What's your best bet?

Get a coffeemaker and brew up a cup of piping hot Prestone®.

Cheap coffeemakers can be found at flea markets, or your basement.      Photo Credit: Jbody.org

Olren Brown of the website J-Body.org came up with this ingenious way to filter used-but-good antifreeze. Drain it from the vehicle, collect it in your choice of a catch can. Next, take an old but working coffeemaker complete with the proper filter, and let it percolate. Eventually the process will yield a cleaner batch of coolant than you started with and you can easily top off your radiator with the finished product. It worked perfectly for his old Ford Ranger and it can work for you, too.

This is what the used coolant looks like before filtering.       Photo Credit: Jbody.org

I wouldn't advise breathing the warm glycol vapors generated by a drip coffeemaker. Its probably better to just stay clear and let it do its thing. Antifreeze is nasty stuff. Its greasy, it smells funny, and its not good for pets or the environment if you dispose of it the wrong way.

The clean finished product, ready for use.      Photo Credit: Jbody.org

Voila! Once the brewing cycle is complete, you can button up the cooling system and top off with coolant. This works way better than the old "filter it through a shop rag" method that I've used for 15 years. I recently went through a thermostat housing replacement on my '98 Cobra after a flush & fill and would up recycling my antifreeze (twice) before getting things right. Hopefully this little shadetree tip will help someone in a similar spot. Thanks Orlen for your advice, and happy wrenching everyone!



  1. Is there an advantage to using a coffee maker with filter? Wouldn't a coffee filter in the bottom of a large funnel serve the same purpose?

  2. Vector: Probably just for the convenience factor of not having to stand around and wait for it to filter. This allows you to fill it with coolant and then do something else, like surf the web for more car parts, while it strains the particles out. I'm not sure if heating it makes it easier to flow through the filter or not, (I got a C+ in chemistry), but I've tried to use a cone filter and a funnel and it seemed to take a while to pass through when cold. It may be worth an experiment sometime. You're 100% right though, a funnel and filter would work just the same. Thanks for stopping by!


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