Mike2001Pro

The radiator is going to be your biggest issue because the water block can be disassembled and cleaned pretty easily and so can the tubes and fittings.
The Pacific RL360 Radiator happens to be aluminum. I saw people recommend baking soda and vinegar to clean aluminum. I might suggest running that through the whole system. I'd be careful of any leaks or spills. The paint residue might come off with some paint thinner but paint thinner is some strong stuff. I saw this stuff here "Motsenbocker 413-01 Latex Paint Remover". This stuff looked pretty safe for getting the paint residue clean without causing any problems with other materials. It might be worth a shot to run that through the entire cooling system.
There is always a way! No road blocks here. - TC Technician
Let me know what you think and keep me posted buddy. We will find what works and make it happen.
(edited)
There is a simple and practical fix for this. Were talking about cleaning up Thermaltake C1000 coolant "gunk" here and that's minor when compared to rust and other metal contaminants.
You may want to fist take a piece of the tube for testing and then try a solutions with that to see what works before running a solution through the whole system. I was also thinking that you could probably heat some water up (hot water - not boiling 100-110c / 120-140 Fahrenheit) and let the radiator soak and CPU block in that for a bit with some vinegar and baking soda and then go out side and take the garden hose to it flushing out the gunk. Just be careful not to warp the radiator/CPU block by heating it too  much and/or by heating and quickly cooling it. (For the CPU block- If you didn't want to take the CPU block apart that is. The CPU block has some components in there but should be able to with stand the heat just fine)
I'll assume you are on a budget so I will try and recommend house hold things. As a computer technician I always heard gamers and techs say things like  "just get a new one those aren't worth anything" . It's very popular for computer people to under value used computer parts. But money doesn't grow on trees and I have never found no value to used computer parts, especially fans.
Aluminum is a metal that could with stand oven cleaner so I was thinking you could spray oven cleaner inside the radiator and let it sit for a couple hours. I'm pretty certain that would work nicely. And then garden hose it again..lol  Believe it or not, it's pretty safe on metals. You just got to rinse it out really good a few times. I can recommend other house hold things that might work for the pump as well if I'm going down the right track here. Let me know.
(For Science! - I've never met my equal, in real life or online)