So after having my car inspected with the coolant topped off and bled in the radiator and reservoir the car still seems to slowly overheat at idle. However, the meter rapidly goes down if I give it the smallest amount of throttle. It seems to be idling so low that the car just wants to shut off. It idles way below 1k revs and if I give it enough gas to just pass the 1k mark, the overheating dies doen fast. Any ideas guys?

 

Sounds like a partially stuck thermostat. Water pumps on this car are fully mechanical in nature. I can't recall a single post about a failed one on here.

I don't know what 1/3 full means. What exactly is 1/3 full? How was this determined.

As mentioned, proper bleeding is vital to proper cooling system operation. When I did my drain/fill, I used the vacuum fill method. Requires an air compressor but absolutely no issues with air in the system afterwards.

 

You can also put higher pressure radiator cap

 

Any car I've ever dealt with, maybe I've just been lucky, I've filled with coolant, started the car, turned the heat on high and just kept topping it off until it reached operating temperature and couldn't take any more coolant. Easy as that.

If problems do arise after filling, then there is an actual problem. Its not that hard to get the air out of the system either. Bubbles want to travel up and while it heats up it builds pressure and pushes the air out of the nearest hole, aka the fill hole or overflow tank.

 

Should one use a higher rated fuse if the current one keeps blowing?

 

The cap just raises pressure and boiling temp what's fuse have to do with it

 

The reservoir was 1/3 full when it happened, but I had everything drained/bled and got any air out of the cooling system. Yet I still have the same issue of overheating when the car is stopped. Its no problem because if I give it a little gas with my foot on the brake during traffic the meter rapidly goes down. I just have to be wary of the meter in stop and go traffic. It's such a strange issue though and the shop couldn't figure it out either. The car isn't throwing any codes.

 

are you sure your fans are coming on. i would check the operation of your fans first. check it by starting the vehicle with a/c off and with a thermometer in the radiator cap opening and watch the coolant warmup. when the thermostat opens the fans should kick on. if they don't you may have an issue with the fan switch or wiring.
if your fans do kick on and temp on the instrument cluster is going hot put the radiator cap back on. switch on your heaters with blower motor on high, not with a/c on. and see if the temp goes down. if temp lowers or does not rise up you may have an issue with circulation on the radiator end. if temp gauge continues to climb with the engine running while at idle and not moving i would next check your temperature sending unit. are you sure the shop you took your car to even did these basic checks?

 

You missed the point. You don't fix a symptom by installing a larger fuse. You fix the issue causing the short, in this case the over heating.

The reservoir holds relatively little volume of coolant compared to the entire cooling system. Have you actually taken the radiator cap off (cold engine) to observe level inside? That would be the first place to look. Proper level is all the way to the top.

 

My comment was after I told him to bleed the system

 

The last gen motors had issues with their thermostats. They went out fairly regularly at about 70K miles. It was the only issue I ever had with my FX.

I'd do a new thermostat and a radiator cap if I were guessing. Might want to hit up the FSM and go through the troubleshooting steps to pinpoint the issue. It's something you'll definitely want to get fixed as blown head gaskets and warped heads are not cheap to fix.

 

This was the same professional shop that completely rebuilt the front end of my car so I assume that they thoroughly did the basic checks, but I will take your info and check myself on my next free day to be sure.

 

I'll go to the dealer and order a new thermostat and cap to see if that fixes it. My shop checked the head gasket and it wasn't warped. They told me that the pressure could be wrong or the thermostat is troubleshooting

 

I appreciate all the advice guys. I'm taking everything into consideration until I find a solution. The last thing I want is for this problem to develop into a costly repair.

 

Wait...so you had a front-end collision that necessitated major repairs? Did this happen only after the car was repaired? I'd still do the factory service manual check myself to see if it's the thermostat. Make sure the cap is the right pressure too.

You can find them here: Infiniti G35 / G37 Factory Service Manuals - NICOclub