G35Driver - Infiniti G35 & G37 Forum Discussion - 2007 G35X

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- - 2007 G35X - Fans don't turn on until 212°F (https://g35driver.com/forums/g35-sedan-v36-2007-08/470435-2007-g35x-fans-dont-turn-until-212-f.html)

2007 G35X - Fans don't turn on until 212°F

Hello fellow G35 owners, please help this completely confused guy out. I am at my wit's end here regarding my 2007 G35X with 132000 miles on it.

TL,DR:

Is this normal cooling fan operation?
A/C OFF: Fans are off and turn on at HIGH speed only at 212°F.
A/C ON : Fans turn on at LOW speed immediately, switches to HIGH speed above 195°F.

Longer version:

So, I previously had posted about the weird behavior of the fans on my G35X and hence I went ahead changed out the entire fan assembly with TYC 621840 from RockAuto per recommendations from this forum. While discussing with a Redditor, I got to know that with A/C OFF, the fans should come on at LOW speed and stay at that speed between 195°F - 208°F, before switching over to the HIGH speed at 212°F. I have tried looking up the cooling fan operation in the service manuals for the sedans but to no avail. The old fan assembly, as well as the newly replaced fan assembly, BOTH turn on at HIGH speed ONLY when the temperature starts creeping over 212°F, with the A/C OFF.

With the A/C ON, the fans turn on immediately and stay on LOW speed below 195°F, switching to HIGH speed above 195°F.

Here is a request to fellow G35X sedan owners, can anyone please confirm if this is normal? If not, where in the manuals could I find this information? Also, do you have any suggestion to fix this? Seems like with A/C OFF, the fans never come on at the LOW speed. I have already tested the cooling fan relay on the passenger side of the car, the only one that I could find, and it works according to voltage specifications in the manuals. Is there any other relay for this?

Please help! SOS!

Look up PCS-10, Power Control Systems. You can put the IPDM into test mode to verify the fan duty cycle, it will have mid duty for 5 seconds then hi duty for 5 seconds.

Are you sure the redditor knew you were talking about the V36 platform cars? Your fans send a scaling duty cycle via the fan control module next to the fans, it doesn't just have low and high speed, it varies the duty cycle as needed but putting it into test mode verifies that 50% and 100% duty cycle are working.

I think he was talking about the V35 platform which used the 3 fan control relays and only had low and high speed option.

Thank you so much for your reply! Thank you as well for recommending changing the fan assembly on my previous post.

Quote:

Originally Posted by cleric670 (Post 7201325)

Look up PCS-10, Power Control Systems. You can put the IPDM into test mode to verify the fan duty cycle, it will have mid duty for 5 seconds then hi duty for 5 seconds.

I did find this test, but haven't gotten around to doing it. I will try this as soon as I can and report back.

Quote:

Originally Posted by cleric670 (Post 7201325)

I think he was talking about the V35 platform which used the 3 fan control relays and only had low and high speed option.

I think he was, cause based on how the discussion was progressing, it seems to me now that it might be a 2004-05 Coupe. But there's just such limited information out there about the V36 platform except for this forum, and I am gonna be honest, I haven't delved deeper into learning better myself. So, I did panic for a while.

The new fans push air much stronger than the previous ones through the rad and I can certainly feel the air once I pull up the hood. I am just still a bit concerned though that the fans do not come on before 212°F. Of course I can only vouch for idle conditions, and I know the vehicle speed and coolant temperature are factored in by the ECM to send the signal to the FCM, but I feel like the fans are coming on too late and during summer temperatures, this could again lead to overheating.

What are your thoughts on that?

I think you should just watch the gauge on the dash, maybe somebody else with the HR engine can take a picture of the temp gauge when the vehicle is at normal operating temperature so you can compare it to yours.

If it's not overheating then I don't see a problem with the coolant temp being 212°. The temperature fluctuates quite a bit across different parts of the engine. As long as your fans turn on and your car is at normal operating temperature on the gauge then you're fine.