My wifes 2003 G35 sedan started to overheat today. It has not done it in the past, and this last week, it has started getting into the high 90's. Today it aproached 100 and started to overheat. This was during driving as well, not just at a stop. Are there any common issues I should fix first? I was going to try the usual process of thermostat, then the water pump if that doesnt solve it. It is full on coolant and has not leaked any. What would be reccomended on the car? Thanks

UPDATE
I changed the thermostat out last night, and still have the same issue. I am not getting coolant circulation(I think). I started the car and drove it around the block, the guage went up almost instantly. The hoses are not limp, but dont have a ton of pressure either(I can squeese it...how hard should it be?). The top hose is hot as hell, and the bottom hose is just warm. This tells me it is not circulating. What would be your reccomendations now? My electric fans are turning on with A/C etc. Is this a water pump issue now? Or could it be there is air in the system somehow? It never went low on coolant, just started overheating. Help please

 

For the car to overheat that quickly, my money is on the water pump. I would say to see how if it overheats at a constant highway speed to rule out the fans, but it sounds like it wouldn't make it to the highway without overheating! After you went around the block (and let the engine cool), what was the level when you popped open the radiator cap? Things you can test before replacing the pump are replacing the radiator cap, doing a pressure test, and flushing the old coolant. If you do the flush, I would just refill it with distilled water, since you are probably about to change the pump anyway.

Good luck.

 

I let the car idle in the driveway for about 15 mins before I drove it. I drove it about 8 blocks total. While idoling in the drive, it did not ever go above halfway.

 

If you didn't get all the air pockets out of the radiator system after you changed the thermostat it can cause the temp to spike up. One way you can tell is let the water cool down and remove the radiator cap and sqeeze slowly the radiator hose or heater hose and see if you get any bubbles, and if so keep sqeezing various radiator hoses until you see no more bubbles.

 

Did you ever get a fix on your car ? Mine is doing the same thing. I'm looking at replacing the water pump but not sure how on this car. I hope the entire timing chain cover doesn't need pulled off. It looks like it has an inspection plate at the water pump. any help would be great.

 

My car had the same problem.. My dealer replace the thermostat and burped the coolant system.. They say it took them a couple of hours to burp..... No more overheating .. Knock on wood

 

+1 water pump and air pockets. This happened to my friends car as well. Took it to local shop and they fixed it within 2 hours.

 

Fyi the gauge is a bit slow, IMO you should get an OBD II reader so you don't get to a high temp during "testing"