Possible blown head gaskets

Good afternoon,

You can do a chemical test to see if there is hydrocarbons in the coolant. You can get the kit at a parts store.

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

I like another way. It is called a leak down test. It is done on each cylinder. Remove the plugs and air up one cylinder at a time and watch for coolant movement in the radiator.

Roy