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Winter antifreeze ratio

OK - does one really need to do a 50/50 ration water to antifreeze mixture or is it just another way to pad the antifreeze makers bank accounts? I live in the upper Midwest where -20 happens occasionally & plenty of zero degree nights. A friend says 1 CUP of antifreeze per gallon water is sufficient. Is it sufficient for Midwest winters?

Get smarter friends because one cup per gallon is not going to protect from freezing at -20 F or C. Engine coolant is what you are working with. It is there to prevent freezing, to prevent boiling and to prevent corrosion. Don’t ruin if your engine is worth much more than what a gallon or two of coolant costs, use the ratio recommended by the auto maker.

Thanks. My friend means well but sometimes doesn’t know what’s up. I have always followed the 50/50 ratio in the past but if a guy can save a buck legitimately, why not? That said, I will be putting 50/50 ratio in for this winter.

50/50 is the way to go. You can measure it yourself or buy premixed.

One cup per gallon will freeze in the temperatures you’re talking about, and the damage could be substantial.

Your friend is misinformed.

Definitely go with a 50-50 ratio. The closer you are to half water and half antifreeze, the more effective it is. I would also recommend getting an antifreeze tester from a store to see how good your mix is. You can get the ones with the balls that float or sink from a Walmart for a buck or two. It’ll let you know just how bad your mix may be. Given that you’re in a cold winter climate, it could be very important to your vehichle. As for the antifreeze folks trying to make more money, they’d be making more by telling people to go with 100% anitfreeze than by going with 50-50. Where you can save is mixing yourself as opposed to buying it pre-mixed where you’re paying to get half a jug of water.

Ignore your friend, 1 cup/gallon is 1/16, about 6%. Look where that puts you on this chart (EG is ethylene glycol, PG is propylene glycol):

First not all coolants (a much better name than anti-freeze) are the same. Some do not call on mixing with water. They should all come with mixing instructions. Follow the instructions.

100% coolant usually does not make a good coolant in the car. In fact it generally will not protect the system from freezing as well as the properly mixed product. Too much will have a higher freezing point than the properly mixed stuff. Too little likewise.

In addition the coolant also must act as a lubricant for the water pump and it also increase the ability of the mix to transfer heat.

Note, there are different kinds of coolant.  Only use what your car's manufacturer recommends in the owner's manual.  The so called universal stuff IS NOT UNIVERSAL.  

Just read the instructions in the owner’s manual and on the bottle and follow them.

In addition to all the good comments on freezing, keep in mind that antifreeze has corrosion inhibitors. With that little antifreeze in the mix, the cooling system will corrode. Tell your friend to set aside the few dollars he’s been saving plus a whole lot more for a new radiator sooner or later.

. I have always followed the 50/50 ratio in the past but if a guy can save a buck legitimately, why not?

Because all you’re saving is a buck (i.e. $1). It’s NOT worth it. My time is far more valuable then just $1.

Toyota sells their proprietary coolant PREMIXED 50:50, so no decison is necessary. Trying to skimp on engine coolant is the ultimate folly!

I did not notice that you drive a Ford. Go to
to find your correct coolant. If you decide to use G05, and I recommend that you do even it is optional, do a final fill and drain with distilled water after you flush with your garden hose. Coolant is compromised by bad water so you can only go 2-3 years rather than the 5 that the original G05 coolant is rated for.

You can find Zerex G05 at NAPA and I think PEAK makes it as well. Both would be a lot less expensive than the Motorcraft at the dealer. YOu might want to pick up a pack of stop-leak pellets at the dealer though. They are used at the factory and it is not a bad idea to replace them. You can find the stuff at the Motorcraft site as well.

I set my customers cars at -35 in Milwaukee, but no BMW ever slept outside on a -35 night.

Since there was a factory specified coolant interval (on a checklist) a BMW shop usually has numerous coolant exchanges going on everyday,there was coolant everywhere.

I hope you believe me when I say all the mechanics did the exchanges, they knew there would be big problems from the other mechanisc if we found out.

Some of the less motivated mechanics would short change people on cabin air filters on e-36’s as they were a pain until you figured them out.

Thanks for the link - wow, is that complicated! Anyone know why Ford would have such a range of different antifreezes? And how are they different?

Been offline for a few days but am overwhelmed by the kind & extremely informative stuff. Copied off the chart & Ford factory stuff for my friend. Can’t wait to show him!
Thanks, everybody, for your greatly helpful feedback.

You could also show your friend the back of his antifreeze bottle. They print the proportions vs. protection data right on the back. Often it’s a table format, sometomes a chart.

Joe, I really have to disagree with you about the universal antifreeze. It really is universal and is the best coolant to use in any vehicle.

There is now a universal propylene glycol and it will work at 100%, unlike ethylene glycol which should be used at somewhere between 50% and 66% concentration.

Good job, Keith. I am amazed at how few people know that it has been quite a few years since antifreeze was changed so 60% actually protects colder and hotter than the traditional 50/50. I know it was before I retired in 1997.

Of course, if they changed it back, I missed that but at that time it was true.

the universal antifreeze. It really is universal and is the best coolant to use in any vehicle.

Not according to VW. I suspect they may not be the only ones.

While using universal supplies may be a real convenience and other reasons, it may not be good in every car. For the owner, there is little reason to use a universal product, when they can get the right (approved) stuff.

Ford is obviously getting away from the higher silicate old-fashioned green coolant and switching to the gold GO5 which has longer life. The siicates tend to precipitate, but they are good, inexpensive corrosion inhibitors. Two down.

I think the orange was really Death Cool and they got out of that experiment very quickly 'cause it was not working for them or GM. The Motorcraft site says it is Dexcool compatible. Three down.

I don’t know what the Dark Green stuff is. Four down.

They now have two coolants in use in production cars. That is not too many considering how many models they have. They must have some specific for Diesel though.