hey guys i’ve replaced the thermostat twice changed all cooling hoses bought new cooling fans, but i’ve had this overheating issue where air bubbles are forming in cooling system it’s like it overheats due to air bubbles forming because when i bleed most air bubbles out of system the car runs like a champ no overheating and i could probably drive it for a whole day no issues but next day would probably overheat or coolant will fluctuate , i do not see any leaks , car runs smooth and still pulls like a beast . i ran a combustion test where the fluid will turn yellow i’m pretty sure i did this test correct i took out 2-3 inches of coolan so coolant wont get sucked in and the test stayed blue, i dont see signs of a headgasket leak like milky oil, smoke coming from exhaust , no loss of power just a weird over heating issue a mechanic told me my symptoms lined up to a leaky headgasket if anyone has any advice it would be appreciated a lot