Radiator Fluid Change 2013 Tacoma

How can I tell if my radiator fluid was changed by a mechanic? For example, I take my Tacoma to a dealership to get a radiator fluid flush ( change ), what if the mechanic decides they don’t want to perform the fluid change, and just say they did? How can I tell if my radiator fluid has actually been changed? I’ve ordered a refractometer for specific gravity reading. Wouldn’t the specific gravity of my 106,000 mile radiator coolant be different than the new radiator coolant? Is there any other way to tell if my radiator coolant has been replaced? In other words, what are differences I can detect between old radiator coolant & new radiator coolant?

 

Usually you can see the difference, old toyota pink has more of a cloudy orange color to it. New stuff is pink to light red and should be pretty clear.

Now if they just drained the radiator and not the block that's only about half so depends what they did on how much difference you would see.

 

I think you're massively overthinking this. If you don't trust your mechanic and think they might charge you for a service they didn't do - FIND A NEW MECHANIC.