Can I use CLR to clean out my radiator?
No, CLR should not be used on a car radiator for two reasons. First, CLR may not be compatible with the internal metals of the radiator. Second, it could have adverse effects if the CLR is not rinsed out completely.

Again, and FWIW, this is straight from the CLR web site and it doesn't say anything specific about being "ok" to use on/in/with one metal vs another (aluminum, copper or brass).....it just specifically says "not to be used in a car radiator for 2 reasons".......

Another FWIW.......on the Prestone jug it says "mix with water".....since tap water is drinkable, one would think tap water would be safe to use/mix (with Prestone antifreeze/coolant) and not cause problems.

 

OP: also know there are drain plugs in the engine block that will help you get the rust sludge out of the bottom of the motor, which is where this most likely came from. I believe they are near the motor mounts but towards the back of the engine. Square female fitting is needed like a 3/8" extension but they are like 5/16" or something stupid.

My coolant was kinda similar to that from PO never doing any maintenance to the vehicle. Replaced everything in the cooling system and flushed the block out with help of the block drain holes.

 

Thanks every one for the thoughts. I'm more then likely going to stay away from CLR and work on more flushes. I haven't tried pulling the drain plugs. I've only Ever hooked up the flushing kit and run water through until clear and pull the radiator hoses off and force some air through until dry.

This is a PO issue. I guess I
Ll clean their mess up. Lol. I love my Jeep