The radiator on a Chevy S10 should last the life of the vehicle. However, over time, the radiator may rust for several reasons, most of which involve poor maintenance. The radiator fluid should be flushed every year, and the coolant to water ratio should be maintained at 50/50. If the radiator does begin to rust, there is really no way to save it. It must be replaced.
Place the catch pan underneath the radiator. Since many S10s use the lower radiator hose to drain the radiator, you want to be sure that the catch pan is under the radiator in the front of the truck. Also, there is no need to jack up the truck, since it sits high enough off the ground that this is not necessary.
Loosen the hose clamp screw on the bottom-most hose on the radiator. This is the drain hose. While most S10s use a drain plug, you may want to skip using this because they tend to seize up. If you attempt to remove it, you're more likely to snap off the plastic insert, and then you'll have to replace it. If you go this route, the plug is on the bottom of the radiator. Use a screwdriver to loosen the plug.
Slide the hose clamp out of the way. This can be a little tricky if the hose is old, but if the clamp is loose enough, it should back off without too much trouble.
Pull the hose off the end of the radiator. Wiggle the hose back and forth a bit while pulling.
Drain the radiator fluid into the catch pan. Make sure that all of the fluid drains into the catch pan so that you do not leak coolant onto the S10's paint.
Remove the upper radiator hose. Loosen the hose clamp screw, and slide the hose off the upper radiator inlet.
Remove the radiator-to-frame bolts with a socket wrench. Depending on the year of your S10, there will be 4-6 bolts that need to be removed to pull the radiator out of the engine bay.
Pull the radiator straight up out of the vehicle.
Install the new radiator. Installation is the reverse of removal.
Push down on the radiator cap and turn it counterclockwise. Pull the cap off and fill the radiator with 50% coolant and 50% water. Replace the cap and run the engine until it comes to operating temperature. Check around the new radiator and the hose attachments for leaks.
