I'm starting a dedicated thread for engine coolant pH test results. Maybe we'll see a trend. If you want to debate coolant types, maintenance schedules, etc...please don't do it in here!
In order to get some context for your test results, it would be helpful if you posted the following:
- Model year of your Mirage
- Coolant...Are you still running the factory fill? Have you changed it? You aren't sure?
- Have you experienced reduced heat output in your car?
- pH level
Here are my results...
Coolant: Factory Fill...original coolant has never been changed
Reduced Heat: Yes...I have tested my car and have symptoms of a restricted heater core.
pH Level: 7
Here is my test strip...
As you can see...my car's coolant is neutral...not acidic. Yet my car also has reduced output on the passenger side...consistent with Doax's discovery of a restricted heater core on the passenger side of the core. So it seems coolant acidity may have nothing to do with the heater core issues some of us are experiencing.
I used Phoenix Systems Double Ended Coolant and Brake Fluid Test Strips. These aren't cheap, but they work with all types of coolant and are well-proven. An added benefit is that you can check your coolant with one end of the strip, and your brake fluid with the other. You can see both of my results in the image above.