Radiator swap

Hey guys was looking for some input. I recently had my fan rip a gash in my radiator on my 87 4.0 xj, well the truck was stuck outta town so I bought a radiator out of a 91 off my buddy and threw it in and drove home, I noticed it actually ran cooler than normal. My question is, can I just leave the system as is and never take the cap off? Or do I just finish the conversion? If so what else would be involved?

You could just leave it as it is, just make sure the cap on the radiator is a higher pressure than the cap on the coolant bottle.

I would finish the swap myself. I just did the open swap on an 89 MJ I just got. It is alot nicer not having to worry about the bottle and the headaches of burping the air out of it are a thing of the past. Just my thoughts on it.

Alright then, So just pick up an overflow bottle and leave the rest of the old system in place?

i just got a piece of hose and looped where the coolant bottle was and put a overflow on the rad