so i drove home from work the other day and my van started to overheat i got home and noticed that one of the freeze plugs if im looking under the hood on the right hand side of the engine underneath the water pump i believe is bad.. how hard would it be to replace this one and does anyone know which one im talking about?

 

year? engine type?
If you can see the freeze plug then normally its just a case of levering the old one out and lightly tapping a new one in place. Normally the problem is getting access to them

Richard

 

if you can access them as the previous poster has stated, they are not hard to replace.
I had one completely blow out on a 69 Plymouth Fury wagon once. To replace that one, I had to pull the transmission, but it only took me about 5 minutes or less to get the new one in.
They make metal and rubber ones, that you just put into place and then turn a nut to tighten them into place for situations where you cannot get a hammer in to tap them in.
The below pic is what the ones I mentioned look like.

 

I just literally did mine, ended up doing all 3 on the back, they can be a pain to get out due to the angle but it is doable. Take your time, took about an hour to do, excluding draining out the coolant and replacing, you may find once you get the freeze plug out, there is a lot of crud behind it (from the plug braking down), try to remove as much as this as possible.