I've seen a couple write ups on doing this but havent seen how long it should take. Anyone have an idea?

 

If you have the right combination of short extensions, flex joints/wobbly extensions it is real easy to do. I've done it a few times. I'd say one hour to remove and one to reinstall, that is plenty of time. You just need to move some parts to get access to the support bracket and related parts.

You will lose some engine coolant and you will want to do a bleed/burp on the system.