I need to get the coolant on my car flushed. It's been over two
years since the last flush.

A lot of auto repair shops offer the coolant flush service.
It will take some time to do the job.

However, the "speedy," 10-minute oil change places also offer
what they call a coolant flush. It can be done much faster
while-u-wait.

Is the coolant flush offered by these "speedy" lube places
an actual complete flush and fill, the same as the auto repair
shops?

Or is it just a quick shortcut that just replaces some of the
coolant?