Hi, I've recently been having overheating problems with my 2004 Infiniti G35x it has 160k miles. My boyfriend changed the thermostat and completely drained my anti freeze and put new anti freeze back in. There's times when it over heats and then other times it's perfectly fine. My boyfriend says it probably has air bubbles in the system still. I continue to put in antifreeze hoping it will help. It's been about a month already and it still overheats once in a while in idle and while it's running. Dont know what else to do. Could it be something else?

 

If I were you I would try bleeding the air out again, if that doesn't work check the thermostat if the problem started after he worked on it you should double check his work he might have put the thermostat in the wrong way. the side with the spring is usually in the engine. And how did he bleed the system?

 

+1 on bleeding out the system, it's a pia to bleed.