My 04 g35 overheated on my way into work today. It was really cold outside and I noticed the temps climbing stuck in traffic. I pulled over, checked fluid level "full" & let it cool down Started it up & made it into work but anytime I stopped in traffic the temps climbed. They dropped drastically if I could go more than 20mph but i live in a stop & go/traffic kind of area.

Its an 04, around 80k miles. I will check the coolant & oil on my lunch break. The fan was working and on so that should be ok. I will mention I have had issues w/the heater core blowing hot air for god know's how long now. That is a seperate issue but that issue is the car only blows hot air in the winter when moving. At a stop sign or in traffic hot air blows cold. The car has never over-heated before and I have owned the car since 30k miles. Coolant was flushed for the heater core issue at least 2-3 times since I have owned the car and it never worked. I usually jack the front of the car up a tad to help with the bleeding process. Seems getting air out of the coolant systems on these cars is a huge pain compared to most.

I plan to try and make it home, replace the thermostat, flush the coolant & do an oil change while I am there.

Has anyone used something like this before and/or know if autozone or oreillys rents these?


I didnt see them listed on their site but was curious because I know bleeding these car's is a huge PITA. On top of that I will have 0 light by the time I am off work and the weather is crap so anything I can do prior to working on it tonight to make this painless is a plus.

Thanks

 

With the engine running, check the hoses to make sure coolant is being pushed through.
Next, I'd check the thermostat. You can remove it and test it in water if necessary.

 

The top hose was hot & pressurized but the reservoir was full "over the full mark". I was literally like 3 minutes away from work & pissed so didn't spend much time looking over things. Just let her cool down enough so I could get into work but I will check it out. Thanks

What's your take on that vacuum coolant kit? Think its worth the coin? I am only debating it because it would also be nice to fix my heater core/heat issue with winter here. This is my DD so not having heat really sucks. Top that off with the G not being the best winter car/snow getting stuck is a bit colder LOL!

 

Follow the troubleshooting steps in the FSM

http://www.nicoclub.com/FSM/G35/Sedan/2004/co.pdf

See page CO-6

Telcoman

 

Most likely your electric cooling fans are shot. This is a real common problem on our cars.

Don't use your Air Conditioner or front window defogger when in traffic until you get the issue fixed. That will cause your engine temps to spike. Put the heat on full blast and not on Recirculate and use that to help pull some of the heat out of the system when you're stuck in traffic and it's heating up.... crack your windows opened a bit in the car if it gets too hot to be comfortable.

 

I ended up doing an oil change, filter change, thermostat change, and tried a flush. The car dosnt overheat but after spending 1+ hours trying to get all the air out it wasnt happening. I am going to take it in to a rad shop to see if they can fix my heater core issue "remove all air, chem flush". If its too expensive I will buy that tool mentioned above, backflush the system & retest my heater core.

For now, its drive-able and not overheating at least. Likely cause: Thermostat

 

If it was your thermostat, it would do it regardless of whether you were moving or sitting still.

I'm pretty sure it's your electric cooling fans in front of the radiator. These go bad on most early G35's at some point.

 

Well it technically was climbing in temps even while moving the other day on my way home but that morning it bounced between hot and medium if the car was moving. Keep in mind temps were cold in the morning, not so much in the evening.

I drove it to work today in traffic and the needle never left the mid mark. The fans kick on and were definitely moving tons of air when I was bleeding air out last night. They seemed to be working ok. I will find out after some more driving for sure.

Before replacing the thermostat last night I also over-heat at idle, however after changing thermostat and fluids I had it running for 1 hour+ in 10-20 minute intervals to burp the air out and never had it creep. The fans kicked on and moved what appeared to be a fair amount of air. They are pretty loud once the hood is popped, sounded like my fal fan's on my weekend car haha. Ill keep ya posted on the heater core problem.

 

I didn't see it mentioned (though you might have already tried), but there's an air relief valve at the back of the engine near the battery to get that last bit of air out of the system. It's supposed to be open when filling radiator with water, fill until water spills from the air relief hole, then close air relief plug. When topping off/bleeding coolant, the heater should be on full blast to circulate through the heater core.

 

That thats the heater core vent access. I bleed air from there but everytime there was air time after time. I may have air getting in the system somewhere or its just a painful process to bleed it all. I did bleed air from there 3-4 times during the burping process though. Heat always on high during etc. One time it sounded like a damn jet when it was pushing air out of the system.

Checked for leaks "none found" although keep in mind I was doing this at 8pm, outside, in the dark with handlights & one tripod light. Garage was full with other toys LOL!

Last year when I tried to bleed all the air out & fix the heater core I flushed the system & bled air from there countless times "this includes on jacks, jack stands, normal ride height etc, i did many different things to get all the air out". I would bleed air from there after everytime the car got warm for a week but never got the heatercore to work properly. I imagine it needs to be backflushed and/or chem flushed. It literally hasnt worked since I bought the car w/34k miles on it but the first couple years I had a different car for winter. Now this car is my winter car so its a different story. Dropping her off tonight to let a local heating/cooling shop take a look at it.

 

jus extra info fsm says to poor the coolant slowly guys to avoid air

 

Yep. I was going to suggest the same thing. Did this every time I've changed my G35 coolant and have never had a problem with air. I never even had to use the block bleeder screw.

And by pour slow... I mean like REALLY FRICKIN SLLLLOOOWWWW.

 

yup when i did my drain refill i had no problems with air

 

Guys I am new to this site. I just recently purchase a 04 Infiniti g35 sedan, after 4 month of owning it with 68 k miles the radiator cracked causing it to over heat. I took it to a local repair shop had the radiator replaced and new thermostat replaced as well I even replaced the cooling fan because the OEM fan motor went bad. My heater works I don't believe to have air in cooling system but for some reason my new fans run more then my other one did and on high after 10 mins of driving it's annoying. I took it to Infiniti they said everything is good my car seems to be working fine which I know it's not because before my repairs I never heard my fans before. I even replaced cooling temp sensor and still same shittt!!!! Plz help any ideas as!!!

 

The ECM controls the cooling fan corresponding to the vehicle speed, engine coolant temperature, refrigerant temperature, and air condition ON signal. The Fan system has a 3-step control [HIGH/LOW/OFF].

See the linked image for specifics of how the fan is supposed to operate based on various conditions: