Hey guys, I am in the works for buying my first Z.  All of this talk about the oil temp. problems is giving me second thoughts though...If Nissan does not ameliorate this problem, what are we to do?  Install our own?  Here's another question too.  I usually drive the backroads of the Santa Monica Mountains as if they were a track; do you think this type of driving warrants an oil and diff cooler?  If it doesn't, would installing the cooling systems make the oil too cold and somehow hurt the engine just as if it was overheating?

Hi Adam,

I think if you do this sort of pleasure driving a lot then you probably should invest in an engine oil cooler.  Since this is southern California, I don't think you need to worry about a thermostat for the oil cooler like you would on the east coast.

For the diff cooler, I would say you probably don't need it for street use or even casual track day use, but if you were doing track days with back to back sessions, or if you install a conventional clutch type LSD, yes then for sure as these run much hotter than the stock VLSD.

The reason is we noticed that early pre-production vehicles had both diff coolers and engine oil coolers.  From some of our experience racing 350Z's and 300ZXes, we have noticed that the 350Z runs way higher diff temps than the older cars because the diff is tucked up high in the body structure and doesn't get much air flow exposure.  The 370Z is exactly the same in this respect.  The 350's raced in SCCA T2 class and Koni Challenge were plagued by diff failure, usually the diff locking up!  Sometimes in as little as 30 minutes of continual track use.  In these racing classes, particularly T2, the cars are in pretty close to stock condition.

When working with Steve Mitchell's time Attack 350Z, we had to continually monitor diff temp with thermal indicator paint, stickers and an IR gun and run carefully as not to exceed 20 minutes or so to avoid diff failure.  Eventually Steve went with a diff cooler.

Since the 370Z uses the same short nose R200 diff and has a high out of airflow position as the 350Z, and after seeing the cooler on the prototypes, we can assume that the 370 is going to have the same diff temp issues as the 350 did under track conditions.  I personally feel that for street use, even hard driving that you will be ok but like I said for track days, avoid doing back to back sessions.

You might want to investigate if the Nissan Motorsports Euro rear diff cover for the 350Z will fit.  This gives 1 quart more sump capacity and has cooling fins.  This is a stock part on euro Z cars.  Its not enough for racing but it might be a good compromise for the street.  Greddy also makes a big pan with lots of fins and an even bigger sump but I don't know if their is chassis clearance in the rear.

Also run high quality synthetic gear lube.

Wow! Very helpful, thanks for your input smartbomb, I can already tell this forum and website is full of good people who truly love the art of driving and the art of the Z.

We are striving to be the low signal to noise ratio unbiased place for the 370z.

Not for use in Southern California where its never too cold.  For wintertime in Michigan, maybe, you might need a thermostat which can easily be added to an oil cooler kit.  Oil needs to get to around 160-170 degrees to vaporize off moisture that can form acids and other bad stuff.

Thats the main reason why short hop driving is considered extreme duty and a more frequent oil change interval is recommended.

 So is this car really worth the buy despite the gross oversight on the part of Nissan.  I mean I don't want to make this kind of purchase without knowing what's going to happen; you know, if I have to put an aftermarket oil cooler on and have my warranty cancelled, or risk it and drive without one.  Any advice?  I really love this car, but this stupid overheating problem is really vexing me!

I can tell you Adam that you shouldn't give it another thought. As far as the oil temps go, I myself had Technosquare install an oil cooler and I have not had the temp climb above the 220 mark under some pretty spirited driving. On the other hand, the low oil temp is a valid concern. I can tell you that my oil temp drops when I'm cruising at a good clip on a freeway in cool air temps and the oil hangs right around the 180 mark. I think it might have dipped below that just a smidge once or twice but never below a temp that would vaporize the moisture in it. Plus, with the fluctuation of the oil temps, it's already vaporizing any moisture/acids anyway so even if it did dip that low, it wouldn't be for very long nor would it make a difference. But I've never seen those temps.

Problem solved on both ends so to speak. Ongoing monitoring is under way with my car but all signs point to go as far as I'm concerned.

I wouldent hesitate to get a 370Z one bit.  Just add an oil cooler.  IMHO, its the best bang for the buck performance car out there.

You know, what worries me though is that Nissan is going to void my warranty with an aftermarket piece like that.  That's something I just cannot afford right now, the warranty would be a must.  I'm torn now...I feel like perhaps I should wait for a time to see if Nissan will start installing the oil cooler themselves or go into a dealership and say, "Hey, I'll buy this car under the condition you install an oil cooler."  Really grind them for it, especially in this economy with not many people buying 2-door sports cars it could be a viable strategy.  Any thoughts?

Your dealer will be clueless.  I don't think Nissan will start installing a cooler, thats what limp mode in the ECU is, a poor mans cooler or failsafe.  The auto industry is hurting so they won't want to raise prices or put cost into cars unless they blow up and limp mode will prevent most of that.

Nissan probably doesnt even acknowlege the problem.

I don't think your warranty will be voided for adding a cooler.  Its against the moss-magnerson law.

Hey Adam,

We wrote an article to address your questions in detail.  Check it out!

http://www.370z.com/Magazine/tabid/64/Default.aspx