Originally Posted by Sayjac
Quote
…... Zerex's green is slightly different than old school green. It's supposedly a hybrid mixing both an organic and inorganic acid along with phosphates and a low level of silicate. It claims the same 5/100 service interval
Link and/or citing to that information? Or is the operative word, "supposedly"?
Zerex Green does claim 5/100 service interval and low silicate formula which would help extend the interval. Silicate drop out, precipitation in original green IAT is what shortened their service interval. Afaik, Zerex Green is the only original/conventional green AF that specifically advertises the extended interval.
Original/conventional green can be found in AP stores ( AZ has store branded) and some may be low silicate, they just don't specifically advertise it like Zerex.
These are the two patents referenced in an TDS for Zerex green:
https://patents.google.com/patent/US4548787A/en
https://patents.google.com/patent/US6203719B1/en
It seems like BASF/Valvoline is using a polycarboxylic acid to keep the silicates stable in Zerex green. Of course, a carboxylate is an organic acid. There's something similar BASF sells in Europe for things needing "old-school" green. It looked like some creative chemistry was done to claim both long life and compatibility with existing silicated green.
CCI and Prestone supply the parts store with their coolants it seems. As much as Prestone would love for everyone to use their new pHOAT Cor-Guard formula, they still sell their older Dex-Clone to Walmart and private labels as well as old-school green under the Prime label and other labels.