A/C and Overheating Help Please
 

My 2003 Sedan started overheating when I have the A/C on. I noticed the electric cooling fan (the one in front of the rad) does not kick in as soon as I switch in the A/C. Could someone check if it does for them? Most cars will, but I just wanted to make sure it’s this way for the G35 as mine does not.

I figure because of this, it’s already over-loading the cooling system and the car is well on its way to overheating. I know the fan is good as it kicks in when the car gets too hot, but not when I just switch on the A/C.

The dash gauge will start reading normal (mid-gauge) around 70°C (160°F) and pretty well stay there until about 95°C (205°F) according to my OBD2 ScanGauge. I’m thinking that to start, I should change the thermostat since it hasn’t been done in a couple of years and flush the coolant as I think normal for our cars is about 85°C (185°F). I’m not going to bother testing the T-stat until I replace it as I don’t want to do the work twice.

Also thinking of changing the Rad cap after if that doesn’t work to bring down the temps at normal.

My biggest concern is that the fan isn’t working properly as out-lined above. With the A/C on, the temp will rise to above 120°C (250°F with the dash gauge running up to HOT) but will cool back down when I click off the A/C but the temps will stay above normal for a while.

Any thoughts and confirmation that the cooling fan is supposed to run as soon as the A/C is switched on is appreciated. Many thanks if anyone has ideas/suggestions.

TIA

:confused2: No ideas anyone???

If anyone could please check their G35 to see if the electric cooling fan automatically switches on as soon as the A/C button is depressed, it would help a lot.

Thanks in advance.

Just went out and checked mine. Both fans come on.

FYI - The warranty has been extended on the radiator fans. I would take it to a dealership and have it looked at.

Thanks for checking.

Since my 2003 is over 9years old, I'm not sure that the rad fans would still be covered. What was the issue, or do you have a TSB to reference?

Thanks again.

fan clutch is shot...


replace

Here's some reading info: https://g35driver.com/forums/g35-sed...-infiniti.html

I'm looking for more info. I believe the warranty was extended to 96mo/110k miles. You may be past that already.

Also, the early 2003 sedans have a different fan setup than the 2003.5+ Sounds like you have an early model sedan.

https://g35driver.com/forums/5960077-post23.html


If you can go to the auto parts store ask then to plug in the obd scanner which will allow them to see live data.

For a fan clutch these are your operating temperatures:

HIGHWAY SPEEDS: 177-183
EXIT HIGHWAY: 183-186
STOP AND GO: 185-191
HEAVY STOP AND GO W/AC:191-194
IDLE W.OUT AC:185-188
IDLE W. AC:188-191

ALL OF THESE TEMPS ARE 100% TESTED. BY ME.

ALSO AUXILIARY FAN KICKS ON AT 203 WITH AC OFF @ 50%
WITH AC OFF 210 @ 100%

k thx :)

^ Good info there.

Does NOT....

this fan is activated via the ecu within a few conditions:

A/C On and pressure switch asking for fan to turn on.

Car over heating: see post above.

Gordgee, I STRONGLY suggest you change your fan clutch and while you are at it, it would NOT hurt to change the thermostat.

Please remember to bleed all of the air from the system. If not you could potentially see this issue arise once more really soon.

I didn't change my fan clutch in time and caused the heads to warp. Then my problem was strange; I had the water being pushed out of the reserve tank. Hopefully you have not caused this damage yet.

I didn't realize that sedans had engine driven fans. Good to know. Learn something every day.

Early sedans some 2004's too.

Thank-you. Excellent information and links. :thewave:

If you need any more help PM me...

I've gone through just about every overheating situation :( with the G.

Eric:

Not sure what you mean by this. Both temps are with AC off? What does the 50% and 100% refer to?

Thanks for your help.