I'm getting ready to replace a leaky radiator (crack along the top. I've had bo overheating issues si I'm thinking of leaving the thermostat alone. My question is would it be a good idea to do a complete flush (reservoir, heater core and engine block) before I refill the new rad? Someone also suggested replacing water pump but I subscribe to if it ain't broke don't fix it. Would using s 'flush kit' simplify things? The last time I changed over a radiator was on my '56 Ford when I was a senior in high school in 1963 so I'm pretty much a novice. And this is my first jeep. I want to keep this as simple as possible as I have age, arthritis and various other issue working against me. Any suggestions would be deeply appreciated. My jeep is an '04 lj, auto and AC. Thanks.