Boiling coolant coming out of reservoir

Hi and thanks for using 2CarPros.

Do not open the radiator cap when this happens. Wait until it is cooled down.

Next, if it isn't overheating and coolant is boiling out of the overflow, chances are there is a head gasket issue. What can happen is this. Compressed air from the cylinders can enter the cooling system. As a result, it pushes coolant out.

First, when the engine is cold, open the radiator and confirm it's full. Then, start the engine. Does coolant shoot out of the radiator? If so, it's a head gasket.

Here is a link that shows how to check for a bad head gasket. Take a look through it and let me know the results.

https://www.2carpros.com/articles/head-gasket-blown-test

Again, let me know the results. I will be able to guide you further once this test is complete.

Take care,
Joe