Oil in antifreeze, headgasket or ?

[Jaygza01]

hello I have a friend who has oil in his antifreeze and i mean bad, overflow tank is full of it, my ? is, that yes his car is overheating, now is it 100% the headgasket or is there a possibility that if I change the antifreeze(flush) and change thermostat would i be able to save his car? oil level is fine, so its not leaking out bad
:smt018

[seth98esT]

Do a compression test. It is more then likely a headgasker if the oil is mixing with the antifreeze. But it may just be old antifreeze or whoever changed it last used tap water instead of distilled water which would turn the antifreeze a brown color.