Finally you posted good information.

This supports the idea to do old school service method scheduling of replacing the coolant which is about 3-5 year and or not more the 50 k miles .

or follow the auto manufacturer service scheduling and keep us in independent service shop’s thriving.

btw dude I use the reason I prefer the testing for % of coolant to h2o is most tend to add water over time instead of coolant. So while both test are valuable in the service world you as a roving freelance mechanic should understand why measuring for % is better when it come to most all vehicle owners?

 

I use only the Castrol coolant test strips because they measure both concentration and pH in one simple and accurate measurement. I have used a refractometer (very accurate and easy to use) and hydrometer to measure concentration as well as a calibrated pH meter (real PIA having to regularly calibrate it) and all are now burried in a box in my van taking up space. Test strip takes a minute all up if your lazy or having to explain the process to a customer.