Heater Core/Radiator/AC -all in one question!

I have a 98 XJ 4.0 that I recently purchased. It blows almost outside temperature air when I turn the AC on. So that obviously needs to be serviced.

When I bought the rig, it had been regularly serviced by the previous owner in every aspect... except the coolant. I'm fairly certain it was never, ever changed! I thoroughly flushed and refilled the coolant, but after about a week of driving, I could tell that some of the brown sludge was still showing up in the coolant. Initially I had about a 1/4" sitting in the bottom of the overflow reservoir, before flushing the first go around.

So... I flushed it again, this time running a gallon of distilled vinegar in the system for a day, and the coolant has stayed very clean. Fast forward a month, and the heater vents are seeping a fog that smells like antifreeze. I've never had a vehicle that needed a heater core changed, but I'm assuming it has a slow leak inside the box, and its breathing out through the vents.

Now the question is...

Do I dive into changing the heater core, or in hopes of not flushing contamination into it, should I clean/replace the radiator and flush the block again at the same time? I can only assume that radiator has some sludge hiding at the bottom which may resurrect itself some day.

Also, is the AC in any way linked to the heater core which complicates things?

My XJ always hovers around 210 in all hi way driving and summer wheening conditions, is that normal? Or should I look at an upgrade of some kind?

Thanks guys!

Sounds like heater core definitely needs changed... If it we're mine, I would DEFINITELY be flushing while it's out. Take the stat out, water pump, whatever you have to to make sure you're getting clean water through everything. Leave the drain out of the radiator, hoses disconnected, and force some water through it that way too (I use a garden hose). After that, I'd prolly put the plug back in and reconnect the lower rad hose and put a quart or so of straight vinegar in there again and let it sit while you're changing the core. Obviously flush all that out and repeat until clean before the initial startup if you're still getting gunk out of it. Replace the stat while you're at it and stick with the 195*.

Its got a newer water pump and brand new thermostat, though I will remove when I flush again.

Is it possible to have the factory radiator professionally flushed at a shop, or is the stock unit considered enough of a problem, that I'm better off replacing with a performance unit? I don't mind upgrading things while I'm at it, but I definitely don't like spending money twice.

So what's the best route?

It sounds like the heater core has a leak>so that must be replaced, Also the 98,s were noted to have bad AC Evap cores,so find out where your AC system is bad, You only want to pull the dash apart once to fix both problems.
210* is the normal operating temp= Nothing wrong there
Its really your call on replacing the radiator ,it is old,it was dirty...if what was in the system ate the heater core,what did it do to the rad core ?