For this OEM radiator, its is a very good idea to replace the lower hose AT THE SAME TIME that you install the radiator. What I found was that after I installed the radiator and had everything hooked up and in place and filled with fluid, the original hose had a bad seal and had a leak at the connection. The set up on this OEM radiator uses a push on coupling with a wire spring that fits on the hose to keep it in place. There is an "O" ring in the hose that over time will shrink and you can't purchase the O ring separately as it is built into the hose. Its much easier to install the hose before installing the radiator. Best to install both parts at the same time to be sure you won't run into a problem after installation or maybe a short time after the installation. I installed the hose after finding the leak without taking the radiator out and just removing the coolant reservoir and it was difficult but not impossible. Took as much time to install the hose as it did to install the radiator. Now that both have been replaced, my truck is running great. One other tip. When you fill the radiator, don't pour the antifreeze directly into the radiator as it can cause air pockets. Better to fill it from the top radiator hose as much as you can. Get a funnel and disconnect the top hose and put the funnel into the hose. Remove the radiator cap. Pour the fluid in slowly and allow it to seep down into the hose. By doing this, you will be pushing the fluid down into the engine and allowing the air to escape from the top of the radiator. Once you can see that the hose won't accept anymore fluid, reattach it, then pour directly into the top of the radiator. My research showed that if you get air pockets in the cooling system, it can cause your vehicle to overheat or have intermittent temperature changes. Don't forget to top off the reservoir.
Posted by Keith (Bryn Mawr, PA) / May 19, 20202007 Chevy Express