coolant test error

[keenMachine]

Hi All,
Had my 2020 Stinger GT with 3.3T in for oil change today, 55,000 km. I take it to local drive thru now, after dealer took 3 hrs, two times in a row (that was with an appt).
Anyway, they showed me the coolant tester showing almost full scale coolant, no water.
Nobody has touched the coolant since it was new, so I suspect the hydrometer was either broken or not able to correctly measure this long life coolant.
Anyone know more about this? Should I buy my own tested to confirm?
thanks
Ken

 

[Volfy]

If nobody has touched the coolant since you took delivery from the dealer brand new, then it's factory fill. Even accounting for topping off occasionally with straight full-strength coolant, your car is probably fine. Dealers are always out of make money wherever they can get away with.

 

[oddball]

I'm curious where they pulled from. If it's the overflow tank, then yeah, that just has whatever was last poured into it. I only put in water, but I'm in north TX so freezing isn't much of a problem.
I'd say just follow the change schedule in the manual. It is best to get coolant from the dealer because there are so many variants now. Can't just go by color (orange or green) like years ago.

 

[Volfy]

Our cars are not particular about coolant type. Any commercially-available plain automotive-type ethylene glycol based antifreeze will have corrosion inhibitors in it and is good for another 5-6yrs, or longer. Few owners ever keep their cars long enough to require more than 1 coolant change. You don't need - or want - any of the mfr-specific coolant types, like DEXCOOL. A lot of the other fancy additive names like OET, OAT, POAT, HOAT & IAT, plus phosphate-free, this-free and that-free, are all just alternative additives that are meant to be more environmentally friendly and required for regions like EU.

 

[D.J.]

The service manual only states that it should NOT be phosphate free.

If I were you, I would go ahead and ignore the test results from the drive-thru lube shop.

The engine in your vehicle has alu-
minum engine parts and must be
protected by an ethylene-glycol
with phosphate based coolant to
prevent corrosion and freezing.