So recently my 04 350z 117k miles has been overheating at idle or at a stop light. The temp gauge usually climbs pretty quick and I start to get nervous if I'm stopped for more than 4-5 minutes. While moving the temps drop and are in the middle of the temperature gauge. First time I noticed it I parked it while the car was hot and went to check the overflow reservoir and saw that it was sitting at the max. While the car is cold the reservoir is at the min line. Car lives in the Midwest so it's only driven during the season and stored over the winter. I brought it into the dealership at the beginning of the season and the car pretty much checked off green for everything except the A/C. The A/C at the beginning of the season blew hot and the dealership diagnosed it as the car just needing to be recharged. They tried shooting dyed Freon/R134 into the A/C line but couldn't find a leak. The A/C now blows cold and the car starts to overheat. Originally thought that the head gasket was out, but didn't notice any white smoke. Any one have any suggestions on what to check? thanks!

 

Are the cooling fans working? When the a/c is turned on, 1 fan will come on immediately. Have you driven it with the a/c turned off to see if it still overheats?

 

Both the fans aren't running. I've been turning the A/C off everytime I get to a stop light to try and prevent the temps from spiking, but seems like it still rises the same.

 

The fans should automatically turn on when the temperature reaches a certain level. It's a fairly common problem with age. Start by verifying the fuses/relays are good. If so, then you can either replace the entire fan assembly or just the fan motors.

I just recently had to do this on my G35. The fans were spinning but very slowly and not providing enough power to adequately cool.

Or, you can just never stop and constantly drive over 30 mph so that enough air flows through the radiator

 

Update: So relays and the two fuses look good. I tried the diagnostic test through the car and I could hear the relays clicking and what sounded like the fans clicking, but not spinning.

 

If the AC is on, Both Fans Should Be Spinning.
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Mine (same year) failed and were replaced under warranty years ago.