My G35 coupe started overheating all of a sudden when I am idle, but goes back down when moving at 20mph+. I'm trying to figure out if it is the radiator fans or the fan motors that might not be working. Here's my question. If I turn on my A/C should both radiator fans be running, just one, or none until the engine gets hot?

Is one for the A/C and the other just turns on when the engine/radiator starts to get hot?

Please help.

 

The fans usually only come on when the car gets hot. Do a search into "purging" the cooling system. Always do the easy/free things first.

 

i'm sure it's not the radiator/cooling system itself. i can drive for a very long period and the engine won't start to overheat unless i actually stop. anyway, i did notice that one of the fans never comes on even though the engine starts to overheat.

also, i was reading the service manual and it said that both fans should either be on or off, and not one or the other at any one time. the bad thing about it was that i already sent my car into the dealership for service and they said it would cost $700 to replace the fan shroud, two fans, and two motor assemblies. I asked them why they just can't replace the motor that is bad and they said that Nissan/Infiniti doesn't do it that way and that I would need to replace the whole thing. i don't see the reason why the fans and the shroud need to be replaced as they are only plastic pieces with no electrical/mechanical aspects to them. I think it's BS, why would sites like infinitipartsusa.com sell an individual motor assembly on it's own. Anyone experience this also at their dealership when replacing a motor assembly for their fans?

I also forgot to check the fuse for that one motor assembly to make sure it was still good before sending it for service. I hope that wasn't the issue, and the dealer isn't trying to rip me off.