This guy says pre-mix is a scam.

He should have tested his hydrometer's calibration with distilled water before jumping to conclusions. I can't even tell if he is keeping the tester level and plumb.
 
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I look at it this way - the cost of 1 gallon of Prestone 50:50 DexCool:Water (distilled or de-ionized I assume) is $14.18, and the cost of 1 gallon of Prestone DexCool Concentrate is $15.18. That means 1 gallon of the premix solution contains 1/2 gallon of DexCool which costs $7.59 so the remaining $6.59 is for distilled or de-ionized water.

Now, I can go to the grocery aisle and pick up a gallon of distilled or de-ionized water for about $1.00.

Since all of my vehicles requires around 2 gallons of 50:50 DexCool:Water, I can either pay $28.36 for two gallons of Prestone Premix 50:50 DexCool or I can pay $16.18 for 1 gallon of Prestone DexCool Concentrate and 1 gallon of distilled or de-ionized water and save roughly $12. I'll save the $12.00.
 
I look at it this way - the cost of 1 gallon of Prestone 50:50 DexCool:Water (distilled or de-ionized I assume) is $14.18, and the cost of 1 gallon of Prestone DexCool Concentrate is $15.18. That means 1 gallon of the premix solution contains 1/2 gallon of DexCool which costs $7.59 so the remaining $6.59 is for distilled or de-ionized water.

Now, I can go to the grocery aisle and pick up a gallon of distilled or de-ionized water for about $1.00.

Since all of my vehicles requires around 2 gallons of 50:50 DexCool:Water, I can either pay $28.36 for two gallons of Prestone Premix 50:50 DexCool or I can pay $16.18 for 1 gallon of Prestone DexCool Concentrate and 1 gallon of distilled or de-ionized water and save roughly $12. I'll save the $12.00.
Yep, this right here. I just did a couple drain and fills on my 2018 Sierra this past week and the distilled water I bought at Kroger was $1.29 per gallon. Got the DexCool from NAPA for around $25 for 2 gallons of concentrate, still have 1 gallon of 50/50 mix left after the 2 drain and files. Took about 3 gallons of 50/50 mix total, so 3 gallons of 50/50 premix would have cost around $45-50 total. And I wouldn't have had a gallon left over either, so if you figure that it would have been more like $70 total for 4 gallons.
 
I have two of that type of coolant tester. The reason I have two is because I misplaced the first one so I bought another. Once I had two, I found they never matched each other and often gave different readings only minutes later. Now I use a refractometer to measure the strength of coolant.
I also use two testers. One with the dial and the other with the floating ball.
 
And one of these WAS about $20.00.
Refractometer2.jpg
 
I look at it this way - the cost of 1 gallon of Prestone 50:50 DexCool:Water (distilled or de-ionized I assume) is $14.18, and the cost of 1 gallon of Prestone DexCool Concentrate is $15.18. That means 1 gallon of the premix solution contains 1/2 gallon of DexCool which costs $7.59 so the remaining $6.59 is for distilled or de-ionized water.

Now, I can go to the grocery aisle and pick up a gallon of distilled or de-ionized water for about $1.00.

Since all of my vehicles requires around 2 gallons of 50:50 DexCool:Water, I can either pay $28.36 for two gallons of Prestone Premix 50:50 DexCool or I can pay $16.18 for 1 gallon of Prestone DexCool Concentrate and 1 gallon of distilled or de-ionized water and save roughly $12. I'll save the $12.00.


Here’s my take as someone that sells a lot of coolants. Over 1m gallons a year.

If you consider yourself an average person, which I consider myself an average person. 50% of people are dumber than you.

So while you may be able to mix 50:50 coolant reliably and use decent water. Someone out there is going to think since it’s yellow/gold/orange, they should mix it with the respective color Gatorade, in a 1:20 ratio.

At the end of the day, coolant blenders make 50/50 for ease of use. Both because some end users don’t want to screw around. And, some are bluntly too inept to figure out how to mix something.
 
Here’s my take as someone that sells a lot of coolants. Over 1m gallons a year.

If you consider yourself an average person, which I consider myself an average person. 50% of people are dumber than you.

So while you may be able to mix 50:50 coolant reliably and use decent water. Someone out there is going to think since it’s yellow/gold/orange, they should mix it with the respective color Gatorade, in a 1:20 ratio.

At the end of the day, coolant blenders make 50/50 for ease of use. Both because some end users don’t want to screw around. And, some are bluntly too inept to figure out how to mix something.
Oh I agree completely with you, and some of those people are/were relatives of mine!

Don't forget that 2% of the population who will want to add some flavor of Kool-Aid of whatever color in order to come up with a custom blend with a psychedelic color - I know a few of them too!
 
There are times where there is a legit need for factory premix - the cooling loops on xEV inverters is one. GM wants DI water and Dex-Cool premix for the Volt/Bolt and their xEV line. Toyota only wants their pink coolant for the inverter - the Mirai calls for an esoteric coolant that comes in a 20L kit with DI water for the fuel cell stack.

I’d buy premix if I need to - deionized water is as “pure” as you can get, distilled water is pretty **** close.
 
I’d buy premix if I need to - deionized water is as “pure” as you can get, distilled water is pretty **** close.

Deionized water is not as pure as distilled water. The deionization process only removes ions, it does not remove organic matter such as viruses and bacteria that may be present in the source water.

Distillation removes both ions AND organic matter.

Deionized water is preferred over distilled water mainly because it's much cheaper to produce--steam distillation is very energy intensive. There are applications (such as medical) where deionized water cannot be used; distilled is the only option.

 
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