Lexus Repair: Maintenance, air pockets, coolant

Question
I've noticed a radiator flush device that fits into the spout of the overflow tank and evacuates the cooling system of all air after draining.  The vacuum in the cooling system is used to check for leaks and then to suck new coolant back into the system eliminating air pockets.  Is this device useful or just overkill?

Thanks,
Bob


Answer
Useful. You have to burp most cooling systems to purge them of air when you flush them - which should be done every other year normally, or half the published lifespan of any long-life coolant for safety.
The good ones put an extreme vacuum on the cooling system, then dump tons of fresh coolant into the system, which changes more of the coolant than you would normally be able too, and does it in a really short order.