A: The air bleeder valve, also known as an air release valve, releases trapped air from the engine cooling system.
Not all engine coolant systems have air bleeders. These are typically used on platforms that tend to trap air because the coolant fill neck is lower than the engine.
The valve, when the engine has one, is usually found on the highest spot where coolant circulates. Some V6 Lexus and Toyotas have a removable plug. Some GM vehicles have a bleeder screw with a hole in the side. Dodge/Chrysler engines, when they have one, will have a bleeder that looks like a brake fluid bleeder screw.
Locating the bleeder nut can get tricky due to how small it is. The best way to find it is to look it up in a shop manual material that’s available to you. If you want to “wing it,” search the cooling system first and look for the bleeder. Again, it’ll usually be at the highest point where coolant circulates. Some models have the valve on top of the thermostat housing, so it may be worth looking for that first.
If you want to remove or replace the bleeder valve, simply turn the attached air bleeder nut counterclockwise.
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