However, there are a couple of areas where air might accumulate and need attention if you're experiencing overheating or other cooling system problems:
* Radiator Cap: While not a valve, the radiator cap is a pressure relief valve and also plays a role in allowing air to escape. Ensure the radiator cap is properly seated and in good condition. A faulty cap can trap air.
* Thermostat Housing: Air can sometimes become trapped in the thermostat housing. When you're bleeding the system (if needed after a coolant change or repair) allowing the engine to run and reach operating temperature with the radiator cap off (carefully and with caution, as coolant is hot and under pressure) can help to purge any trapped air in this area. There is no separate bleed screw on the thermostat housing itself.
* Upper Radiator Hose: Sometimes gently squeezing the upper radiator hose while the engine is running (again, *carefully* and *only when the engine is warm, not hot*) can help dislodge trapped air.
If you're experiencing cooling system problems, it's best to not try to force air out yourself unless you are experienced in auto repair. Instead, take your Impala to a qualified mechanic. They have the tools and expertise to diagnose the root cause of any cooling system issues, which might not simply be trapped air. A pressure test of the cooling system is often a very effective way to diagnose problems such as leaks that are contributing to air in the system.
