There are two checks you can easily do on your coolant: whether you have enough of it and if it’s still protecting your engine in cold temperatures.

Prepare the vehicle Open the hood and find a place to set your multimeter. Open the coolant reservoir or radiator cap to access the coolant.

Faster is not better when it comes to engine coolant flow rate. The purpose of a radiator is to support heat transfer, which is a time-dependent process.