The Chevy S-10 has been around for many years and has featured a few different engines, including both four- and six-cylinders. The procedure to change the coolant remains fairly universal regardless of whatever engine is in the compact truck. Chevrolets use a Dex-cool antifreeze with different qualities than ethylene glycol antifreeze. It is reddish-orange in appearance. You should replace the antifreeze in your S-10 every other year.
Drive the S-10 up onto the ramps, and apply the parking brake.
Release the hood latch and open up the hood. If the engine is hot or warm, allow the engine and cooling system to cool down before proceeding.
Slowly remove the radiator cap. Allow any pressure built up inside the radiator to escape through the radiator cap slowly before you fully remove the cap.
Crawl underneath the front of the truck with the catch pan, and use a screwdriver to remove any splash shields that may be covering the bottom of the radiator on your model S-10.
Place the catch pan beneath the petcock on the lower passenger side of the radiator. Turn the petcock counterclockwise by hand to open the valve, and allow the coolant to drain thoroughly from the radiator into the catch pan. If your radiator does not feature a petcock, remove the lower radiator hose in order to drain the radiator. Do this by loosening the clamp on the radiator side of the hose with a screwdriver (for a band-clamp style) or a pair of channel locks (for a spring-clamp style).
Tighten the petcock (or replace the lower radiator hose and clamp).
Add the radiator flush additive into the radiator, then fill it with water from the garden hose. Replace the radiator cap.
Start the engine and set the heater to high.
Siphon the antifreeze from the coolant reservoir into the catch pan. Drain the fluid in the catch pan into an empty jug for disposal. Replace the catch pan beneath the petcock of the radiator.
Shut the engine down once the cooling fan turns on. Allow the system to cool again.
Drain the contents of the radiator again into the catch pan, then close the petcock. Open the radiator cap and fill the radiator with water. Keep the garden hose nearby.
Start the engine again and allow it to run (with the radiator cap off) until the cooling fan starts. Open the petcock over the catch pan--be careful, because the water will be hot.
Begin filling the radiator with the garden hose at the same rate the water is draining from the petcock. Once the water looks clear, shut the engine down and allow the water to drain into the catch pan. Close the petcock when the radiator is fully drained.
Add the radiator coolant additive to the radiator. Fill the radiator with Dex-cool antifreeze (1 gallon mixed with 1 gallon water). When the radiator will take no more, fill the coolant reservoir to the full level.
Start the engine with the radiator cap off, and allow burping coolant to fall into the catch pan beneath the radiator neck. Squeeze the upper and lower radiator hoses occasionally to purge more air from the cooling system. Add more mixed antifreeze when necessary.
Lower the S-10 off the ramps, and check the coolant level in the radiator. Add coolant if needed. Replace the cap, and drive the S-10 for 10 to 15 minutes.
Allow the engine to cool again. Recheck the coolant level in the radiator and reservoir. Add more coolant if necessary.
