I hope you don't mind me jumping in. Roy is correct saying it is likely a circulation issue. Here is an easy way to check:
Start the vehicle and turn the heat on high. Allow the engine to run until it reaches operating temp. Then you can turn the engine off. Open the hood and feel both heater core hoses. Both should be hot (one may be slightly warmer simply because it is a supply line). If one is cool and one hot, there is a circulation issue.
The heater hoses are behind the engine and attach to the heater core. They are rubber hoses approximately 1" in diameter. See attached pic.
Also, let us know if the engine is reaching operating temperature.
Here are the bleeding directions. There is a bleeder on the thermostat housing. I'm not sure if that is what you are using.
1. Fill the radiator and the coolant reservoir to the full cold line with GM Goodwrench DEX-COOL (R) or Havoline DEX-COOL (R). To ensure sufficient engine cooling, freezing and corrosion protection, maintain the protection level at -37 C (-34 F) lower.
2. Wait for two minutes and recheck the level of the coolant in the radiator. If necessary, add coolant to radiator until the coolant level is at the base of the radiator fill neck.
3. Install the radiator pressure cap, making sure the arrows on the cap line up with the coolant recovery tube.
4. Place the heater and A/C control in any A/C mode except Max and the temperature in the highest setting.
5. Start the engine and allow to idle until the louver radiator to coolant pump hose is hot.
6. Cycle the engine speed up to about 3000 RPM and back to idle five times. Slowly open the bleed valve on the top of the thermostat housing for approximately 15 seconds to expel any trapped air in the cooling system.
7. Close the air bleed valve. Do not overtighten.
8. Allow the engine to cool to outside temperature. Ensure the coolant level in the reservoir and the radiator are at the proper levels.
Let us know what you find or if you have other questions.
Monday, March 22nd, 2021 AT 12:53 PM