http://www.lislecorp.com/divisions/products/?product=94


Here’s a little tip.

Open the air bleeders and pour in your water until you see water come out of the air bleeds and close them. After this never open them again.
Start the motor and keep the funnel about 1/3 full and wait for the thermostat to open.
After the thermostat opens rev the motor a few times and witch the bubbles.
NOTE: Do not let you motor get to hot (over 200).
I turned on the AC and turned the temp to full hot and fan on high.
This will run the fans on the radiator and pull heat off the water through the heater core.
I left my motor running and removed the funnel and put the cap radiator on.
If you don’t do this the water will boil before the fans come on and blow water
out of the funnel.

Here’s mine at work, it come off the Matco tool truck.

 

Yep, they work good. They're around $25. They come with various adapters.

 

I've got one as well. Mine is yellow, but it's made by the same company. Ditto on the temp. It will boil and throw coolant everywhere....trust me.

The only thing I would add to the directions is to make sure the overflow is full hot level and to make sure the radiator is full after the first full cool down. If not, fill it full and that should do it if your system has no other issues.

 

I actually made one of these using a gallon jug of water, I just removed the radiator and fitted my jug on the top of the radiator; it worked great.