You don't have to send off your coolant for processing. Try this. Wait till the radiator coolant is cold. with the engine off, remove the radiator cap and make sure the coolant is up to the neck. Start the engine. if there is an exhaust leak into the coolant, the coolant will jump out of the neck of the radiator. You can tell about where the exhaust is leaking into the exhaust by removing the plugs and looking for coolant contamination. Revving the engine up will make it jump higher.

If the head gasket is gone, chances are good you have a warped head and it takes someone who really knows what they are doing to "fix" a warped head by milling or any other method to keep the head gasket from blowing in the future.

If you still wanna test for hydrocarbons, test kits only cost about $40-50. Most auto parts stores dont carry them but NAPA does and they're usually available online. They're often called a "block test kit" or something rather. They either look like a turkey baster or have a hose sticking out of one end rather than the baster bulb and come with a 12 oz or more bottle of blue fluid. looks like this:



All you do is let the engine get up to operating temp with the radiator cap off, fill the clear vial with about an ounce of fluid, and stick the pointy end of the tester into your radiator creating a good seal. You pull cooling system gas through the fluid with the bulb or pulling a vacuum on the hose. If the fluid turns yellow (or very slightly greenish) youve got hydrocarbons in your coolant gasses causing your problems. Have fun.