We need to start with pressure testing the system and make sure there are no leaks, and it holds pressures.
Here is a guide that will help with this:
If it holds pressure, then we need to move onto checking the head gasket and make sure it is not blown.
If all this passes, then I would suggest changing the radiator cap and finding out if this solves the issue.
Please run through all this info and let us know what questions you have.
Monday, February 14th, 2022 AT 6:55 PM