A/C not cooling in traffic 2006 M35 180k miles

[mcarman430]

Hey folks, wondering if anyone else has seen this issue. My M35 has 180k miles and just started blowing hot air in traffic two days ago. First time it happened I noticed the engine temp went way up but came right back down when I got moving again. The other couple times it happened the engine temp was normal. It only seems to happen when I don't have air moving thru the radiator. At cruising speed the A/C will freeze you to death. Not sure where the thermostat is on this thing. It probably wouldn't hurt to change that regardless. I checked the coolant level and it was at the minimum mark in the reservoir tank so I added a little. Belts are tight with no squealing. I guess I am suspicious of the water pump but hoping that isn't going bad. Also, the check engine light never even blinked so it either isn't bad enough to trigger a fault or it isn't anything being monitored. Any help will be greatly appreciated. Thanks in advance,

[ArmedAviator]

Your radiator fans are not working. The A/C evaporator depends on these fans in addition to the engine radiator.

It's likely a blown relay, controller, or fan motor. There's steps to test and isolate the failed device in the service manuals.

In the mean time, avoid slow speed travel or using your vehicle at all - an overheated engine can warp blocks/heads/head gaskets and then a simple repair ends up costing thousands.

[steve_c]

Your radiator fans are not working.......It's likely a blown relay, controller, or fan motor...
In the mean time, avoid slow speed travel or using your vehicle at all - an overheated engine can warp blocks/heads/head gaskets and then a simple repair ends up costing thousands.

Spot on Reply!

Additionally,
Early 2006 built M's experienced pre-mature failures with the fan controller unit (mounted on radiator fan bracket).
It was a factory recall. Call your local Infiniti dealer & kindly ask them to search open recalls on your vehicle. Have your VIN # handy.

[mcarman430]

I will check that. Do you have a link to download the service manual? Also, any wiring diagrams/schematics would be great.

I know at least one of them is running since I can hear it. I did notice once that it sounded like they were running on high speed when I first started the car so that makes sense.

Thanks,

[ArmedAviator]

Are both fans running when the A/C is on or the engine warmed up to normal operating temp?

Ensure that the A/C evaporator and radiator fins are not clogged with bugs and road debris, including the space between them. Ensure that the fan shroud is properly installed so air is actually drawn through the components to cool them rather than from around them. Also check for broken blades on the fans.

[mcarman430]

Assuming that both fans should be running at the same time then I might have a bad temperature control on the fan assembly. I swapped the wires to the fans and the right side fan runs on the output for the left side fan and the left side fan stopped. Are there any preferred brands for temperature controls and relays?

[mcarman430]

Thanks guys. Very helpful info! I have an appointment tomorrow to get the fan controller and the accelerator pedal module recalls done.

[steve_c]

[quote="steve_c"....Early 2006 built M's experienced pre-mature failures with the fan controller unit (mounted on radiator fan bracket).
It was a factory recall. Call your local Infiniti dealer & kindly ask them to search open recalls on your vehicle. Have your VIN # handy.[/quote]

Thanks guys. Very helpful info! I have an appointment tomorrow to get the fan controller and the accelerator pedal module recalls done.

You are very welcome, and happy to see you on the forum! These are great cars!
Your symptoms perfectly described the fan controller recall defect, so it is good to start with that before spending time & money diagnosing & throwing parts at it!

Good luck!