[Z06] 2002 zo6
you can try to do it on car and or pull the radiator and pick and and use compressed air to blow out all the crap stuck in the fins. you also could just replace the radiator if it's a 100k mile car. a new ac delco radiator is $200 shipped
very common issue. the other is a failing thermostat and the water pump if OE is on borrowed time if you have an 02 as well. same with the hoses. at 15yrs the cooling system on basically any car needs to be refreshed
I also have a 2002 Z06, and followed this guide when I blew out the radiator and AC Condenser, it worked extremely well. At the same time I flushed the old coolant out because I think it was original. Replaced with fresh dexcool and water.
Car runs 20 degrees cooler than it did.
HTH
John







