Possible Causes:
* Low Coolant Level: This is the simplest and most common cause. Check your coolant reservoir. If it's low, you have a leak somewhere in the system (radiator, hoses, water pump, etc.). Top it off with the correct 50/50 mix of coolant and distilled water (never just water). But don't just top it off and drive away! Find the leak first.
* Thermostat Stuck Partially Closed: A thermostat that's sticking partially closed will restrict coolant flow, causing overheating. When the engine gets really hot, it might eventually force enough coolant through to temporarily cool things down.
* Cooling Fan Not Engaging: The cooling fan is crucial, especially at idle or low speeds. If it's not coming on when the engine gets hot, the engine will overheat until it's forced to cool down. Check the fan's operation and the fan switch/relay.
* Water Pump Issues: A failing water pump may not circulate coolant efficiently. This is less likely given the rapid recovery, but still possible. Listen for unusual noises from the water pump.
* Air in the Cooling System: Air pockets can prevent proper coolant circulation. This is often related to a recent coolant change or repair. Bleeding the cooling system might be necessary.
* Radiator Issues: While possible, a completely clogged radiator would likely cause a more sustained overheat. The rapid cooling suggests it's probably not the main culprit unless there's a very partial blockage.
* Faulty Coolant Temperature Sensor: An inaccurate sensor might be giving the wrong reading to the computer, causing the system to react improperly (or not at all).
Troubleshooting Steps:
1. Check Coolant Level: This is the absolute first thing to do.
2. Inspect Hoses and Connections: Look for any visible leaks, cracks, or loose clamps.
3. Check the Radiator: Feel the top and bottom radiator hoses when the engine is running. If the top hose is hot and the bottom hose is cold, there's likely a restriction somewhere in the system.
4. Listen for Fan Operation: Does the fan kick on when the engine reaches operating temperature?
5. Check the Thermostat: (After the engine has cooled completely!) This might require removing the thermostat housing. Inspect the thermostat to see if it opens and closes freely.
6. Bleed the Cooling System: If you've recently worked on the cooling system, air pockets might be the problem. There are specific procedures for bleeding the system for your S-10; consult your repair manual or an online resource.
Important Note: Ignoring an overheating engine can lead to catastrophic engine damage. Do not continue driving your S-10 if it overheats, even if it cools down quickly. Investigate the problem thoroughly before driving again. If you're not comfortable diagnosing and repairing the problem yourself, take it to a qualified mechanic.
