Anyone have one for a 420a?

 

It's easy. Get the manual for your car, clear out the coolant, flush it out with a hose, remove the old thermostat, install the new one, fill it up with the 50/50 mix, run the motor to purge the bubbles by leaving the cap off and fill as necessary, fill your resevoir all the way up, drive your car around a bit, done. You'll notice that your resevoir bottle is at the "full" line and the excess has evacuated the bottle.
See, easy

 

how do I flush it?

 

Stick a hose in one of the openings and the water will flow freely since the thermostat is what keeps it from flowing. The water pump's impeller won't hinder flow much.

 

i never flu****, i usually just drain it with the plug at the bottom of the radiator. But he is right, just unplug the termostat and plug the new one in. Pretty simple