Originally Posted by c00lkatz
Another way to do it is to remove the pan, drain the fluid, clean the pan and install the new filter, then top it off with some fresh fluid, like normal. But instead, take the cooler inlet hose, stick it into an empty bucket, take the cooler outlet hose, stick it into a bucket filled with fresh fluid, then let the car run. This will allow the pump to drain all the old fluid while sucking in new fluid at the same time. Then you just shut it off when fresh fluid starts coming out of the drain hose. That way you don't accidentally run it dry, and you still flush the whole system at once. Be sure to check the fluid level afterward. If it's too low, top it off, too high use a MityVac/Vacuum Pump and siphon the excess out. That's a tool anyone working on their own car should have anyway. Very handy little device.
Haven't had to do it on my Focus yet, but I've done it on other cars with great success.
If i didn't have a BG flush machine this would be the only way i would recommend doing this on your own. Personally i flush my car with 16 quarts of fluid :)
I like overkill. Its better on a car that gets driven hard. Even though i use cleaners and additives i still change my fluid every 22,000 ish. 103,000 k on it and runs perfect.