Hi All,

I'm new to the Infiniti scene graduating from the Maxima. I just recently picked up an 05 G35X with an automatic tranny.

I've noticed my electric fans are on quite often at idle - the outside temp has been mid 60's-low 70's. The temperature gauge reads right in the middle. I hooked up my OBDII scanner and monitored the temperature and the fan cycles. Based on the OBDII my temperature ranges about 204-208, even with highway driving. So after doing some searching, it appears the normal temperature for cruising should be 185-190, so I suspect my thermostat is on the fritz.

Before I did searching on temps, I was actually thinking the IPDM may be at fault for the fan. I was actually monitoring the behavior of the fan when it cycles on and off. According to the FSM, the fans should come on Low at 208 and high at 212 without the A/C on. If A/C is on, the fan comes on low at speeds below 50 regardless of temp. Once above 50, it should shut off unless the temp hits 208 and which it will turn the fans on low.

Sooo, the fan appears to be coming on as specified in the FSM. What is odd is the fan won't shutoff when the temp drops below 208 all the time. Primarily while I'm iding. It appears to work correctly while cruising, but it did take an extra second or so for it to shut off. So, when I'm in the state where it doesn't shut off at idle and the temp is under 208, I can command on the A/C (the fan is already running) and shut it back off which then makes the fan shutdown. The process can be repeated once the temp reaches 208 again. Has anyone ever got to that detail with the fan? Maybe nothing is wrong and that is normal. I guess I'll need to change my thermostat and repeat the test...

Thanks
Jim

 

Before replacing the thermostat try this ancient test, remove your radiator cap...run your engine up to normal op temp which is just below half gauge. If your radiator fluid is moving your thermostat is fine. Here's something to make note of if you're ever in a situation where you car runs hot at speed and cools off when slowing down you have a thermostat that's not opening all the way...been there. Enjoy the ride!
Gary

 

Thanks for the reply Gary. I think it's the thermostat for sure. I removed the radiator cap and watched it get to temp using the scanner. Additionally,my temp gauge remained in the middle The coolant never moved that I could see (It stayed right at the top of the radiator with a little spillage the warmer it got). I would have expected it to drop level a bit and begin flowing strong. I suspect it's a lazy thermostat.

When cruising, the temp would get up to 210 but the fans kicked in bringing it down 204, 206 or so, and when in traffic it hovers 204-208. It's like the thermostat is regulating it at 204 vice the 180 the FSM states it supposed to be at.

The car is definitely fun to drive...

Thanks
Jim

 

Just hooked up my scanner to get some live data info.

Fan kicks on at 205-208 degrees....clicks off at 195 degrees.

Cruising on the highway, no WOT it sits in the 190-195 range. Wot blasts drive this up, but stopping and coasting or idling will drop the temp almost immediately.

When idling, and the fan kicks on, the temp drops to 195 or lower within 30 seconds. 195 seems to be the OFF temperature.

Ambient temp was 60 degrees. I'm sure a warmer day might see slower response time to cooling.

 

Hey, good info Mustang5L5 - Much appreciated...

Thanks
Jim

 

Just a quick update:

Changed thermostat today - Bled out the air in the system - Car temperature is running between 185-190 cruising and the fan is now shutting off at idle. Glad I realized the fan operation and catching early before getting stuck on the road...

 

Just installed a Mishimoto rad. Things seems a bit cooler.

Idle: ~183
Cruising: ~179
Slow driving (1-3mph): 195

Again, this is in Seattle in the Winter (about 38 deg outside).

We'll see in the dead of summer.

Elec fans supposed to come on at 203. That's what it was when I was burping the system.

 

Where did you get the Mishimoto radiator?


I wonder if there's a temperature mod to change when the fans start? I don't like the fact the fans kick in so late @ 200F+. I know every vehicle is different for optimal engine temperature, but hanging around int he 190's feel better than watching the temp climb past 208F+.

 

That's normal operating temperature for every car I've ever worked on, don't be fooled by instrumentation that doesn't even tell you the actual temperature. Hot oil is more efficient and the only reason to be running a lower temp thermostat is for race engines, engine start to overheat around 230F so that's the point where you should start to worry.

I don't think Uprev can modify fan temperature points but the standalone units can or you just make it a separate system.

 

I suppose your right. Currently using the bluetooth adapter with torque app and the g35 vq engine coolant runs hotter than my other Infiniti vehicles. The Vegas desert doesn't help; need to look into a better radiator. Hovers in 208-210 with full fans and rarely ever drops. That doesn't happened with my Infinit suv (mechanical fan w/ electrical fan).