hello everyone,I have a 2006 infiniti g35x,with 135k. I was travelling this summer and had the car sitting for about 4 months. when i came back and took it out for the first time i noticed that there was no heat at idle. The next day I also noticed the engine overheating so i assumed it was a low coolant problem and proceeded to fill up the engine coolant. The overheating stopped and i took the car into the infiniti dealership to have a system bleed done to get rid of the air pocket. I took the car home and it was ok for about 4 days. and it started giving no heat at idle again. i took it back and they re-bled it and told me that this year of g35's were really hard to bleed. again i took it home and it started it doing it again and this time i noticed the temperate going up almost to the hottest level and coming back down when i accelerate. I took the car back once again and there first guess was a blown head gasket which was my nightmare. but after they did a carbon test and checked the oil to see if it was a milky color he said he cant be sure about it being a blown head gasket. IM SO FRUSTRATED because an INFINITI dealership cant give me a proper diagnosis on an INFINITI and went on to refer me to another mechanic which i find rediculous. Im confused and dont know what step to take next. i drove the car home today and ran a few errands and the heat seems to be working ok and the engine temperature isnt fluctuating but im sure its just a matter of time before it started doing the same things again. i have noticed a burning smell, i think its burning antifreeze but i dont think its a blown head gasket because there no white smoke or moisture on the exhaust. in the past few days my fan was running very loud and not stopping the whole time i was driving, i checked the coolant level and i filled it up a bit (not the reserve but the other side) and now the fan is not turing on at all but there is still no heat at all. i have no idea what step to take next and whether its the thermostat,water pump,or the worst case scenario a blown head gasket or if its simply more air in the system. which doesnt make sense because clearly all the problems are stopping after each time i had it bled but gradually getting worst. so clearly there is more air getting in from somewhere

 

The air pockets can be a real beotch to get out and sometimes it takes multiple times to do it.

 

yeah i agree with you but why is it that every time i had it bled,all the issues stopped but they slowly start coming back. how is more and more getting back in? or is air pockets even the problem?

 

Do you have lack of power? If so, could be head gasket (you'd see coolant in the oil too). If not, and you're smelling burning coolant, it sounds like you have a leak at the thermostat housing and/or a water pump issue. Do you see any visible signs of dripping, even if it's a drop or two?

 

i havent noticed a lack of power,the dealership did a carbon test and it passed so they dont think its a head gasket. how noticeable would the lack of power be ? and my mechanic noticed some coolant around the reserve tank thats why he thinks there might be a leak causing the burning smell.

 

Honestly, depends. If it's just starting to go, it would be noticeable throughout the power curve. If it's "omg, this is blown" then you'd barely be running, dumping all kinds of fluids all over the road and make a horrendous noise. So, somewhere in between? hehe.

Edited to add: Loss of power throughout the power curve should not be an assumption that you have a blown head gasket. There are plenty of things that could cause that. Just saying that a head gasket on its way out could give you loss of power.

 

lol no theres no leaks like that and power loss that ive noticed. everytime i get it bled,everything works great after. so either there is more air getting in from somwhere,or they havent got all the air out even after 4 f*** times,or its a thermostat/radiator/water pump/ and my nightmare, the headgasket. i never thought getting a diagnostic would be so hard, especially out of the INFINITI dealerhship. my own mechanic is smarter then the idiots at the dealership that charge triple the amount

 

Do you have a Nissan dealership close? Maybe they could give it a look as well? If you're not seeing coolant in the oil and do not notice loss of power, it sure doesn't seem like a head gasket. Like you said, probably still some air in there, but they should have bled the system sufficiently after 4x's. Or you'd think.

 

Oh, one last thing to check... if you search the forums for "fan clutch" there are several threads about the AC not working at idle. I have no idea if it would be the same symptoms for heat. Just something I was thinking about. I'm in Florida and I have some issues with my AC not running as good as it should at idle, so I may swap out the fan clutch to see if it helps. (no problems with overheating/erratic temps though)

 

So did you ever figure out the problem? its been 6-7 months now and i have the identical problem. so frustrated!