Radiator/Coolant Filler Neck / Water Inlet

I have replaced my radiator filler neck today (2007, rx350) by followed George's tip I attached below:

"See the u shaped clip? Pull up one end with a small hook or flat screwdriver then the whole clip will come out of the groove. With the clip out twist and pull on the neck and it will come free. The neck is sealed with an O ring to the radiator so clean the mating surface then wiggle the new neck into place and snap the clip in the groove.
Goes without saying that you need the engine cold to do this."

By the way, there is no O ring in my case, and it took a bit longer for me to remove the neck after took off the U shape clip. And it is not easy to install the new neck to the radiator, I used some coolant as lubricant to wet the filler and neck and a small hammer to hit on a solid plastic piece which I held and made contact with the neck. In that way I finally get the neck into 90% of it's position, and put the u shape click on, use the hammer to hit couple more times, then the click fell into position. Also, in the beginning, I used the new neck to practice how to put the u shape clip on and how to take it off.