Hi
I have a 2005 G35 Coupe with 188,000 miles. It overheats in the summers while driving with the AC off, or when the AC is on.
The coolant levels are normal and no leaks..
That leaves the radiator fans to be the problem.

I have the full service manual. However, I cannot find where the radiator fan relays are.
Here is my idea of doing diagnostics here:
1) find the relays and see if they are bad. if they are, change them first and see if the overheating stops.
2) find a way to check if the fans are running, and if they are not, then the fans need replacing.
3) replace radiator and fans at the same time.

My main questions are:

1) Where are the relays located ? (could not find them next to the battery.)

2) If i want to replace the fans, do I need to do a coolant flush since I have to take off the radiator too ?

3) Can I use a radiator pressure test kit or some other coolant pressurize kit (about $200) to "burp" the air bubbles out or something. I know in the Porsche Boxster that I have, this kind of kit helps refill coolant instantly and you pressurize it as is without having to try all the weird air bubble removal methods.

Thank you.

 

This should help with your relays:

https://g35driver.com/forums/general...-location.html


I dont remember if you need to remove the radiator in order to get the fans out. Watch a youtube video to be sure. But I have replaced my whole radiator before and I just filled it up with coolant when I was done and never had any issues with trapped air in the system.