Tools You'll Need:
* Drain pan (large enough to hold several gallons)
* Wrench (likely a 10mm or 12mm, depending on your drain valve)
* Funnel (optional, but helpful)
* Gloves (to protect your hands)
* Safety Glasses (to protect your eyes)
Procedure:
1. Locate the Drain Valve(s): The most common location for the coolant drain valve on a 1999 Chevy Astro is at the bottom of the engine block, near the radiator hose connections. There might be a second drain petcock on the radiator itself. Locate both if possible. Your owner's manual is your best guide for exact location.
2. Position the Drain Pan: Place the drain pan under the drain valve(s).
3. Open the Drain Valve(s): Carefully open the drain valve(s) using the appropriate wrench. Turn the valve counterclockwise (most are this way, but double check).
4. Drain the Coolant: Allow the coolant to drain completely into the drain pan. This can take some time.
5. Close the Drain Valve(s): Once the coolant has stopped draining, carefully close the drain valve(s) by turning them clockwise.
6. (Optional) Flush the System: For a more thorough cleaning, you can flush the cooling system. This usually involves refilling the system with clean water, running the engine for a short time, and then draining it again. Repeat as necessary. This is more advanced and only necessary if you suspect contamination.
7. Refill the Coolant: Once the system is drained (and flushed if you did that), carefully refill the cooling system with the correct type and amount of coolant. Your owner's manual will specify the proper coolant type (usually a 50/50 mix of coolant and distilled water). Consult the manual for filling procedure, which usually involves filling the radiator and then the overflow reservoir.
8. Bleed the Air: After refilling, run the engine for a few minutes to allow the coolant to circulate and bleed out any trapped air. Check the coolant level in the overflow reservoir and top off as necessary.
9. Check for Leaks: Once the engine has cooled, carefully inspect the system for any leaks.
Important Considerations:
* Coolant is toxic: Handle with care and dispose of it properly according to local regulations. Many auto parts stores will accept used coolant for recycling.
* Engine Temperature: This is crucial. Working on a hot engine could result in severe burns.
* Pressure: The cooling system is under pressure when the engine is hot. Releasing this pressure rapidly could cause coolant to spray.
* Owner's Manual: This is your best resource for specific instructions related to your vehicle. The location of the drain valves and the specific procedure may vary slightly.
If you are uncomfortable performing this task yourself, take your Astro to a qualified mechanic. It's a relatively straightforward job but requires care to avoid injury and damage.
