ok, my thermostat is new and working as well as my coolant system is flushed and is running better (only overheating when driving city speeds with a/c on or sitting in traffic with or without a/c on). if i'm on the interstate or speeds upward of 55 mph temp is fine even with a/c on (and it's actually cool or cold). i took my 2005 g35 coupe to firestone last week and they said it was the fans. both the fans come on, but there is no set time that they come on as well they do not seem to come on together, but i could be wrong. (like i said, they seem to have a mind of their own) does this seem like the fans or motors themselves, or the relays? my car sat for about 2 months or longer while i was out of town and had to be jumped a few times because of a dead battery (if this makes a difference to anyone as far as the relays go). also, i had no problems with my car at all before this time period in which it sat. any help is greatly appreciated. thanks.

 

both fans should engage at the same time

 

Infiniti recently extended the warranty on the fans. You should give them a call.