[QUOTE=TheWeatherman;72269]Weatherman, you are correct, but still the heat is going to be much higher down south than up north. Not that the north will not have issues, but I'm just pointing this out because down here we are already hitting 90+ degree weather. Vermont was in the 50's this past weekend. But enough of this, just edited the above post to include some of the survey data.

Again any word/knowledge about G37? Thanks and sorry to mis-speak above.

[QUOTE=ricer333;72272

Weatherman, you are correct, but still the heat is going to be much higher down south than up north. Not that the north will not have issues, but I'm just pointing this out because down here we are already hitting 90+ degree weather. Vermont was in the 50's this past weekend. QUOTE]


Ricer, you're definately right about the southern states getting hotter and are right about them having the more frequent problems. That is totally the issue. (Again, sorry to be that guy.)

Humidity does in fact affect cars multiple ways. In the case of intake air, it changes the air's density, and more importantly changes the oxygen density (how much available oxygen to burn in a liter of 'air' at a given pressure). As for cooling, humidity in the air changes the heat-transfer properties of the air, which again affects cooling (it makes your car hotter for much the same reasons it makes you feel hotter).

Edit: I'll give you that the car doesn't rely on evaporative cooling like skin does, but still, the heat-transfer properties of humid air are going to be different.

We're not talking about the intake part of this. This is a radiator issue, not an MAF issue. Elevation & pressure is the biggest factor in what you're talking about, not so much humidity.

After numerous thermodynamics classes, the humidity you speak of for cooling is totally different. You're talking about latent heat processes which pretty much don't affect your radiator. Radiators rely on the movement of air over the exchangers which is a conductive process, not a latent process. Your A/C works on latent heating/cooling, not radiators. Actually, humid air can hold more heat than dry air, which would make it better to have humid air running over your heat exchanger. It's similar to a moist adiabatic process vs. dry.

Don't give people ideas about humidity causing this issue. It is completely irrelevant. Any engineer or atmospheric scientist knows this.

Our numbers indicate that our radiators aren't doing much for our oil temps. Water temp in the radiator is fine, but the radiator water isn't getting enough heat out of the engine oil (not enough transfer between the two). Therefore the cooling of the block itself is a factor (engine bay heat). You don't think there's an effect there?

Yeah, with pure heat, not humidity. If anything, humidity would help, but in way so small that it would barely register. Again, heat conduction vs. latent heat processes.

I LOVE IT!!! I haven't heard (or read) the word adiabatic in almost 10 years since my engineering days :icon18:

Ha ha! Thanks for understanding Spearfish, but you know as a scientist, that's how it really works with a car! I just wanted to make it clear so people who go outside and think it's humid think it's going to make your car overheat faster than a dry day. Another common misconception is the thought of a car feeling a wind chill. Sure, it rids heat faster when it's cold, but when you have a windchill of -80F, your car only feels the outside air's temperature. Good stuff, good stuff.

Weatherman no wonder it feels so hot when the temp is over 100 f on a low humidity state like ca and las vegas compared to 85 f humid states. i can't stand 118's in vegas on summer...

A quick note on my last trip. I drove from Cincinnati to Atlanta for my high oil temps cure. Just after crossing the KY (not jelly) TN border on I-75 you begin a climb up a fairly hilly stretch. The ambient temps were 62-65F. Prior to this the oil temp was running at about 220F. Five minutes into the climb I was at 235F with the cruise on 70 mph.

Back to the latest topic of humidity. Has anyone tried a mister on a car with the oil cooler added? I used one on an inter-cooler once. The mister came on at a preselected boost level. It seemed to help but you needed a lot of water capacity for a hot day using boost on a frequent basis.

Final note: On the way back from Atlanta I had absolutely ZERO oil temp issues.

Something that has been bothering me lately:

We have been seeing high oil temps. Nissan included an oil cooler with the preview cars. We "know" high oil temps are a problem. Nissan is coming out with an oil cooler. There are oil cooling kits already on the market. Most people are aware of the oil temp issues.

However, Nissan also included a differential cooler on the preview cars. We don't have an oil temp gauge for the differential oil. If Nissan has data that we don't have (and they obviously do, otherwise they would not have included the oil cooler on the preview cars) it suggests that the differential oil is also likely experiencing undiagnosed/unseen temperature problems as well.

There is very little discussion/data about the differential temps, but Nissan obviously thought there might be a temp problem there, otherwise why would they include a differential cooler? I'm starting to think this may be the underwater part of the cooling iceberg - a potentially big problem, but completely unseen at this point in time.

What's considered normal oil temp? Even in hot (80 degree +) weather.

On 80 degree days, my 370 hits about 220. I read somewhere that if any car hits 260 or near this, you're in trouble?

Nissan did exactly the same thing when they introduced the 2003 350Z. A differential cooler was installed in their introduction test car to the media and others. The reason: not to overheat and stress out the stock VLSD and show it's inherent weakness with continuous tracking.


Since I believe the 370z's differential is the same as the past 350, the only reason for the diff cooler install in the test car is to prevent the stock VLSD from crapping out on the track test.

Yes, the Viscous LSD turns itself into an open diff when it overheats ... and it doesn't take much to make it do that.

I just removed the rubber insulation where the hood meets the windshield, and removed the engine cover (plastic top that says VVEL and stuff), and removed the covers over the battery and brake fluid area. I am hoping this helps the oil temps keep cool. I will post the results.

My temps have been hitting 240+ daily now since it has been in the high 90's and low 100's.