* Low Coolant Level: This is the most common and simplest cause. If the coolant level is low, there's less pressure in the system, allowing the hoses to collapse when the engine cools and creates a vacuum. Check your coolant reservoir and add coolant if needed (using the correct type for your Impala). Look for leaks around the radiator, hoses, water pump, and engine block.
* Coolant Leak: A leak anywhere in the cooling system (radiator, hoses, water pump, thermostat, etc.) will lead to low coolant and pressure, causing the hose collapse. Inspect all components carefully.
* Clogged Radiator: A severely clogged radiator restricts coolant flow, leading to overheating and pressure fluctuations. This can cause hoses to collapse during cooling as pressure drops.
* Failed Radiator Cap: A faulty radiator cap can't maintain proper system pressure. If it doesn't seal correctly, coolant can leak out or the pressure can fluctuate wildly, causing hose collapse during the cooling-down phase. Replace the cap if it's suspect.
* Failed Water Pump: A failing water pump might not circulate coolant effectively, leading to localized overheating and pressure issues. This can manifest as collapsing hoses.
* Blocked Thermostat: A stuck-closed thermostat prevents coolant from circulating properly, causing overheating and pressure build-up, then collapse during cooling.
* Head Gasket Failure: While less likely to directly cause hose collapse, a blown head gasket can introduce air into the cooling system, leading to pressure fluctuations and potential hose collapse. This is usually accompanied by other symptoms like white smoke from the exhaust, overheating, and milky oil.
Troubleshooting Steps:
1. Check Coolant Level: This is the first and easiest thing to do.
2. Inspect Hoses and Connections: Look for cracks, bulges, or loose clamps.
3. Check for Leaks: Carefully inspect the entire cooling system for any signs of leaks (wet spots, drips, etc.).
4. Check Radiator Cap: Ensure the radiator cap is functioning correctly.
5. Feel the Upper Radiator Hose: If it's completely collapsed and hard when the engine is cold, it's a strong indication of a vacuum issue likely due to low coolant or a leak.
If you're not comfortable working on your car yourself, take it to a mechanic for diagnosis and repair. Ignoring a cooling system problem can lead to serious engine damage.
