I have an '05 GT with just shy of 80k on it. Keep on thinking at eleven years old and change that I should change out the coolant. Was visiting my brother, a major car buff, and he said just check it with a tester. Never thought of that!

I also have a Yamaha FJR1300 from '04 never changed the antifreeze in it either. Did it a few weeks ago, it is a BIG chore on that critter. Hadn't thought of the "testing" thing on it. The old coolant came out looking pristine, like new, but changed it anyway.

Meanwhile on the GT. I went to Prestone's site, found a "checker" which I picked up at the local auto parts store. When I sucked up the coolant in the tester it was clear and clean as you can desire. And the pointer basically pegged at the top of the scale for hot and cold protection. This caused me to do a check on my Subaru, maybe the tester was defective, the readings on the Subaru fell into the normal readings/scale.

Now, the reason I type, is that I had run across a "ChrisFix" video on how to test and change out coolant. He had an electrical check to make on the coolant. Did it, (my brother is going to try it, never heard of it either) and GT passed successfully. Think I'll just leave my coolant alone. Incidentally, over the last few years I ask my Dealer if I should worry about coolant and such, they keep saying I'm good-to-go.

So, this "electrical test" is to see if you might be having electrolysis going on in your engine causing degrade of your metal and gaskets. To test, you take a Volt/Ohm meter and set for DC Volts 20 limit. Put your positive lead into the coolant (not touching metal) and touch the negative lead to battery ground. A reading of less than .3 is desired. .3 or more, one might consider changing the coolant. Then, you start the engine, same story on the .3, near it or over it a coolant change might be in order. The GT came out in the vicinity of .1

ChisFix had four tests for coolant, sight, specific gravity, electrical and PH. I skipped the PH, the other three had such good results I figured the hell with PH.

FYI FWIW

 

I would be interested in what other folks say. I had a Taurus a long time ago, and I neglected to change the antifreeze until it was too late. I was always springing a leak somewhere. I have changed the coolant on my 07 GT simply because I didn't want any problems (car has 22K on it and sits all winter). I figured it is cheap insurance. I made sure to use the Motorcraft Gold coolant as well. I would like to keep this care for another 20+ years.

 

My last two family cars were a '78 BMW and an '89 GMC 4x4. which I sold a 269k and 238k respectively. I guess to sum it up my "deal" on the BMW was "goody, I'm working/tinkering on the BMW" and "damn, I gotta work on the GMC."

I know I changed out the coolant on the BMW many times, I think for awhile anyway I did it once a year. The radiator still had to be cored/rodded out at least once that I recall. The GMC had the "new" plastic type radiator, that sucker never heated up, I know I changed out the radiator once, but, I "think" I recall it was more of a leak at the top or bottom or something. Yes, I'm pretty damned sure that GMC NEVER heated up, even when an extended idle or workload was performed. FWIW