i have an automatic 2009 g37 coupe with 151k miles.
ever since i got it, it started overheating.

I took it to 4 mechanic shops and they did a pressure test on the coolant system and there is no leaks,

it has been bled out by mechanic shops and me myself and every time they do it they say "there was a massive air bubble in your engine, but we got it out and now its fixed." and then the next day its overheating again.

I've replaced the thermostat and the valve cover gaskets, and it is still overheating.
every time the system overheats coolant spits out into the coolant tank that's in the front of the engine bay. i think i may have a unique problem.

it seems to me that air is somehow getting sucked into the coolant system because every time i re bleed it i have to put damn their half the jug of antifreeze in there or more.

PLEASE SOMBODY HELP ME THIS IS MY FIRST CAR AND I SPENT ALL MY SAVINGS ON IT AND IF I CANT GET IT FIXED ITS GUNNA **** ME OVER

 

Has the radiator cap been replaced? if not, recomend getting one from the dealer, bleed it out again and see what happens.

 

Beefychicken is right, I'd start with the radiator cap as coolant essentially expands (when hot, also releasing pressured gases into the reservoir) and contracts as it heats and cools; the radiator cap is critical in this process.

Excellent explanation of a cap's functionality here:
If your dealer doesn't have one in stock or because they are likely closed on the weekend, I'm sure one from Napa or another local auto parts location would be sufficient since these are well understood mechanical devices built to manufacture specifications.

Next, you will want to check fan operation with an OBD reader as there is a coolant temp switch which turns on the fans via a Fan Control Module (FCM) at I believe 280ish F.

Note that the FCM and the fans themselves sometimes fail as our cars are at least a decade old at this point.

@ILM-NC G37S had to replace his fans once and ran across similar issues discussed here: https://www.myg37.com/forums/engine-...x-problem.html

Regardless, if the cap has never been replaced, I'd replace anyway as this should be a standard maintenance item around 70-80K miles (as it was on older cars, newer cars avoid recommending because any proactive maintenance raises the "Total Cost of Ownership" calculation).