Quick demo of how to use a combustion leak detector to test your engine to see if combustion gasses are present in the cooling system. This is a good indication or a faulty head gasket or damaged head or block. This particular kit was purchased from Harbor Freight but here are links to similar kits on Amazon:

Block Tester BT-500 Combustion Leak Test Kit
https://amzn.to/2Vrnfd5

Block Tester BT-600 Replacement Combustion Leak Test Fluid 16 oz
https://amzn.to/3ChyAx1