Appropriate Ph for coolant?

[Wdeertz]

I recently had all my fluids tested by a lab. The coolant came back with a Ph of 6.67 and the lab indicated to replace immediately. The coolant only has about 250 hours on it so I was surprised by the results. The coolant is Valvoline G05 Zerex which states it’s for heavy duty diesels. I had a new container of Valvoline G05 Zerex available so decided to test the Ph and it came back at 6.7 so the lab results aren’t surprising given this information.

I’ve tried to google the appropriate Ph for coolant but couldn’t find anything definitive other than there was a consensus it should be greater than 7. Did I get a bad batch of Valvoline g05 Zerex? Anyone care to share their coolant lab results in particular as it relates to Ph?

 

[TJM]

Coolant pH should definitely be higher than 7.0 Neutral water is 7.0. Coolant should be more basic. Basic coolant keeps corrosion to a minimum.

 

[jleonard]

250 hours, but how many years has that coolant been in there?
I always thought ph of 8 to 10 is a good.
When it gets acidic you want to flush and replace or use additives to get it back in range.

 

[Wdeertz]

Coolant pH should definitely be higher than 7.0 Neutral water is 7.0. Coolant should be more basic. Basic coolant keeps corrosion to a minimum.

Don’t disagree, so does this mean the 4 gallons of Valvoline g05 Zerex coolant I have is a bad batch? I tested a newly open container and the Ph was 6.7.

 

[Larry M]

I agree with jleonard on the ph range .

Something’s wrong with your coolant or your testing. No offense meant but the specifications say typical ph is 8 with a range of 7.5-11.

 

[Wdeertz]

Coolant is only about a year old with about 250 hours. I don’t think my Ph test is off, what are the chances my test results and the lab would be identical?

As I said I still have 4 gallons of this unopened/unused Valvoline G05 Zerex, maybe I got a bad batch. I may reach out to Valvoline and ask them what their formulation should be.

 

[C lectric]

Coolant is only about a year old with about 250 hours. I don’t think my Ph test is off, what are the chances my test results and the lab would be identical?

As I said I still have 4 gallons of this unopened/unused Valvoline G05 Zerex, maybe I got a bad batch. I may reach out to Valvoline and ask them what their formulation should be.

Their answer would be interesting and helpfull.

I test for the DCA levels, like litmus paper sort of, fairly often but I have NOT sent the coolant to a lab for the Ph.

 

[Larry M]

I run the same coolant in our Sprinter van. I just did a test strip/ph paper on some I have in the garage and it indicates plus 9 ph with a 50/50 distilled water. I tried figuring out their date codes without success.

I’d reach out to Valvoline as you suggested. The picture I posted on the product information before was from their web site. I should have attached the link but here it is.

https://sharena21.springcm.com/Publ...2d889bd3/8469eb8c-e29c-e711-9c10-ac162d889bd3

 

[H2O_Doc]

Zerex spec sheets say the pH could be 7.5 to 11.0. That's a crazy wide pH range for a spec. Not sure what they are thinking. I'd personally change brands.

But, note that for aluminum protection, most manufacturers are using an organic acid technology, that purposely keeps the pH slightly lower for better corrosion protection on aluminum.

I'd be curious what method you are testing your pH? Strips? I don't trust them. I'd trust a *good* pH meter, but good meters are >$500.

We manufacture glycols for industrial use, and our glycol pH is 8.0 for systems with aluminum.

 

[rslifkin]

Zerex is HOAT (hybrid organic acid technology). Looks like the spec sheet says 7.5 - 11 is acceptable, but 8 is typical.

 

[Wdeertz]

I've reached out to Valvoline and they confirmed a 6.7Ph was unacceptable. They are having me send in sample of the coolant from the unopened/new containers so their lab can test it. Will upgrade the group once I hear back from them.