What I do is:
Engine is cold.
Have the new sensor with a new o-ring on it.
Unplug the old one from the blue plug.
Pull the clip.
Use your fingers or some pliers to start pulling the old one out.  Have the new one in your other hand.
As soon as the old one is out start shoving the new one in it's place until the coolant stops coming out.
Look at the old one to be sure that the old o-ring came out with it.  If not you are going to have to pull the new one out and fish the old o-ring out.  If you got both the sensor and o-ring then just finish pushing the new sensor into place and then reinstall the clip and plug it in.

If you do it quickly you won't loose enough coolant to really matter.  Maybe a few tablespoons full.

Hope this helps,
Ken Wilford
John 3:16
www.vanagain.com

-------------- Original message --------------
From: Jeff Lincoln <magikvw@GMAIL.COM>

> I tried searching the archives for this but it kept timing out on me - so I
> am turning to you.
>
> I have a new Temp II sensor for my 90' 2.1 - Can anyone give me any tips,
> warnings, or advice on changing it? Does the old sensor just pull out - do I
> need to seal it with anything? I understand I'll get a coolant bath when I
> remove the old one - how much of a bath? What should I expect?
>
> Again sorry for all the questions but I am hoping to make what should be an
> easy replacement easier with the wisdom of the list.
>
> --
> Thanks,
>
> Jeff
> 90' Carat (It's Blue, It's Beautiful, It's naked inside - IT'S ALIVE!)
> 86' (We call this one Parts)
> 85' GL (Sidelined and feeling neglected)