Premixed Blue Coolant

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I have a 2010 Subaru Outback which takes Subaru blue long life coolant. Pep Boys has a gallon undiluted for about $15.00. On a Subaru forum was advised to use the premixed long life blue because it has deionized water, not distilled. Apparently deionized water is not easy nor economical to purchase. Does anyone have opinions on the superiority of deionized water vs distilled? Frankly I have used tap water for most of the last 35 years with no apparent problem. I have read city water reports and fail to understand how a few parts per million can affect cooling system??? In the last year or two have switched to distilled water for rinses and flushes because of low cost. Is deionized water worth the extra expense of a pre-diluted blue coolant?

Scott
 
I don't believe that whoever supplies Subaru's coolant is actually using lab grade DI water.
 
For use in diluting antifreeze, there really is no significant difference between distilled water and deionized water.

The difference between distilled and deionized water is in the process used to get to the final product. Distilled water begins as regular water and is heated to it's boiling point, and the vapors are collected (condensed) when the vapors hit a condenser filled with cold water. Deionized water starts off with regular water also, but it usually is "forced" through a membrane to purify it. In both cases the various dissolved minerals, salts, and other microscopic matter originally in the water is left behind.

I use distilled water from Walmart since it sells for about $0.88/gallon whenever I need distilled/deionized water.
 
I note that my wife's German iron requires the use of deionized water. Use of distilled water will void the warranty. [censored]??? As a chemist, I can't see what the difference would be unless the deionization process is poor and leaves residual ionic material behind in which case it would cause unwelcome deposits.
 
Originally Posted By: boulderdentist
... Is deionized water worth the extra expense of a pre-diluted blue coolant

No. Get the PB OEM concentrate and use distilled water with it, it will work fine.

DI vs distilled water has been discussed on this sub forum before. IMO, the answer linked sums it up best... https://bobistheoilguy.com/forums/ubbthr.....W#Post2474198

As for the vehicle specific forum, typical in my observation of advice coming off those type forums.
 
Originally Posted By: AndyinAL
http://www.hyperlube.com/c3/super-coolant-c8.html

I have always used distilled water but I came across this last month and it has me wondering. There is a link in the product description linking to a note about not using distilled water.

That article is full of inaccuracies and gets linked here from time to time. Here is a thread and a post I made a year ago on the subject:

https://bobistheoilguy.com/forums/ubbthreads.php/topics/4113105/Re:_Ph_balance_of_coolant?#Post4113105
 
Originally Posted By: Boomer
I note that my wife's German iron requires the use of deionized water. Use of distilled water will void the warranty. [censored]??? As a chemist, I can't see what the difference would be unless the deionization process is poor and leaves residual ionic material behind in which case it would cause unwelcome deposits.

Can you post the exact language from your owner's manual (or wherever you saw it) regarding the water and warranty coverage?
 
Originally Posted By: Reddy45
I don't believe that whoever supplies Subaru's coolant is actually using lab grade DI water.

Really? How would you know?
 
Don't have an opinion on water but I suggest using the Subaru cooling system sealant sold at the dealerships. Unbelievable that they haven't been able to resolve their head gasket problems after what, 30 or more years? My wife's 2010 Forester started losimg coolant at 120,000 miles.
 
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