I'm not trying to negate anyone's experiences but I think my points remain.

To the best of my knowledge...
A. No one has objectively or scientifically demonstrated "how hot is too hot" with regards to today's engines and engine oil or that the temperatures owners are experiencing are actually a danger to the engine.

B. No one has objectively/scientifically/under controlled circumstances demonstrated when/under what conditions the engine oil temperatures rise.

Until the above has been done by someone with no ax to grind; all we have are anecdotal stories and the anecdotal stories that have been presented have been all over the board - pretty much the only consistency rests with those who track their cars. The other obvious problem with anecdotal stories is that it is absolutely impossible to know if what someone is claiming is accurate - again, I'm not trying to insult anyone but this is an internet forum; anyone can say anything so if someone builds an opinion on those stories they don't know if the foundation is, to borrow a phrase, made of sand or of stone.

I think we also need to keep in mind that this site; as do other enthusiasts sites represent a small percentage of the public who own 370s which makes it statistically risky to assume a wide-spread problem.

In any case, I think arguing about it, regardless of one's opinion, is fairly pointless...this horse has been beaten to death until even the blood stains have been separated into their molecular parts.

Live long and prosper.

AMEN NASH! :icon18:

To these points specifically though, this graph says a lot about (A):

http://images50.fotki.com/v1514/phot...andlife-vi.jpg

And as far as (B) goes, the obvious factors that contribute to a higher oil temp are: Time spent at high RPM values, Ambient temp, airflow to the front of the car (and thus vehicle speed), and engine load (uphill worse than downhill, full throttle worse than half throttle, etc).

You guy's must work for Nissan, if not they should be sending you checks. If there's no issue here, if this is only in other peoples minds, then why did Nissan put oil coolers on all the new Z's they sent out to the magazines for testing, they don't put them on other Nissans when they are being tested, they know there is an issue here, the coolers prove it. You mentioned that there is no scientific, controlled studys on how and when the overheating happens, how about everytime I drive my car. If you were having this issue with your car, that would be all the scientific evidence you would need. You need to study up on engine oils an see how the oil begins to break down when it is overheated to the 240-250 range. At this point, at whatever percent of breakdown, it is lubricating the engine less and less, which leads to engine wear and internal problems.

Nissan already told us. If you're racing the car put on the cooler. Who says oil breaks down at those temps? What oil? Those graphs are so ambiguous. Who did the study? Who says our engine is designed for thick oil? Viscosity is the thickness of the oil. You know, why am I even responding? This was all talked about ad nauseum before. Call Nissan if you're having a problem. Read my posts about my conversation with the quality control engineers. That will answer your questions. Done.

Actually I do work for Nissan and have been very open about that (in fact, you can take a look at the sticky thread sitting beside this one (http://www.the370z.com/nissan-370z-g...i-vehicle.html ).

I’m pretty sure that I haven’t and I don’t think anyone else has said that the problem is only in other people’s minds but it is true that what one person perceives to be a problem does not mean it will be perceived that way or actually be a problem by/for someone else.

<o></o>As to the coolers on the test vehicle; I suspect that it’s because Nissan knew that the magazines doing the testing were going to drive the piss out of the 370s on the track. I think the one point everyone seems to agree on is that running the car on the track means you need an engine oil cooler as did the 350 before it and likely as would most modern vehicles today that don’t already have a one.

With regards to “other Nissans”; I’m not sure what other Nissan’s you are referring to but I doubt you know if they put oil coolers on other Nissans being tested or not (I know I don’t know) and if they did, I would suspect it was for the same reason I suggested above.


What kind of temperatures are you seeing every time you drive your car? Have you documented this with your dealer? If so, what did they say? Would your driving style get you a ticket (or in jail) if a police officer were behind you each time? Have you filed complaints with the NHTSA or perhaps an appropriate state agency or returned your car under you state’s lemon laws?

I’m not trying to be flippant here; I’m really not…but if your car is giving you a serious problem every time you drive it then I encourage you to take action until you get it resolved one way or the other.

I will admit up front that I’m no engineer; I don’t know if you are or not; so there is a lot about this I don’t know.

But I do know that all oil breaks down and I know there are many variables that cause that breakdown and how quickly it happens. I also know that heat is one of the biggest contributing factors to engine oil breaking down. I also know that the flashpoint of the oil is one way to measure how easily/quickly an oil will breakdown with heat and that synthetic oils have a much higher flashpoint and resist breakdown due to heat much better than natural petroleum oil. I’ve also been told by someone much smarter than I am in such matters that 220 degrees is about perfect for the 3.7L.

What I don’t know is, if 220 is the preferred temperature, is there a significant/measurable risk to the engine with the oil running into the 240 or 250 or whatever range (however often that happens/however long that happens)…I don’t know if good synthetic oil is good enough to negate those kinds of concerns if you are changing your oil every 3 months/3,000 miles.

Well…I think the molecules from the bloodstains are now down to their individual neurons and electrons at this point…I’m truly sorry if you are having a serious problem with you car and I hope you get it resolved to your satisfaction; whatever that takes.

Wait for it... :rofl2:

A) Thanks for the graph but what oil was tested? Was it synthetic or non-synthetic? How old is the data and where does it come from?

I guess what I'm asking is how applicable is that graph to the 370 using a high-quality full synthetic oil?

I think another appropriate question would be, and I don't have any idea what the answer would be; how much in terms of days/weeks/years/miles driven will the "Max Life" be compromised if, for example, your engine is always running at 230 rather than the max life you would get if it's always running at 180?

In other words, does it mean you'll get 1,000 less miles in total out of the life of the engine or 50,000 less? Don't we need to know that to properly gauge just how significant all this is?


B) I think we can assume all those are factors but I don't know that they explain why some people seem to have "constant" problems while other don't seem to have any. :confused:

Funny about that Huh? Chances are this car will be long gone from your personal stable long before any oil temps issues (real or perceived) rear their ugly head...

My car has about 650 miles and I have tracked the temperature gauge for the last couple of days. For the record my car is a base model w/ a 6 speed and I drive to work 33 miles each way. The ambient temperature in the afternoon has been around 90F-92F and I drive conservatively. My top speed has been 65 mph and I have maintained that speed for about 25 of the 33 miles. My oil temperature has not risen past 215F (on mark shy of the 220F indicator). As I log more miles I will repeat at 70 mph and report what the temperature gauge indicates.

Thanks Robert, for your honest reply there. I may be a bit more concerned about this issue than some. I pre-ordered a 350-Z, 8 months before the '03's came out. The alignment issues were a common problem with the Z's and in those early days of the 350's, tires were wearing out quickly, and Nissan didn't resolve the problem, just gave some people some new front tires and said...problem resolved, and then fixed the real issue a year or two later. It looks like this may turn out the same way. I really liked my 350 and only put the very best of oils in it, I used Amsoil, and changed it every 4,000 miles, long before the oil was worn out. The car developed very serious oil leaks, which Nissan fixed under warranty. Then later my car started using oil more and more. Nissan told me to do an oil consumption test at the dealer, which I did. It was determined that the car was using 1 quart of oil every 380 miles. Yes, you read that right. The dealer told Nissan that I had an aftermarket exhaust on it, and that was enough for them, it was my fault...case closed. Further testing on my dollar, revealed that the oil retaining rings were bad and the oil was just blowing past them and out the exhaust. That meant either rebuilding or replacing the engine at a cost of 4 to 8 thousand dollars. I decided to take a loss and sell the car as is, and figured the new Z would be more trouble free. Now with the brand new one there is a fresh new oil issue. So, I guess you can see why I am a bit concerned. I don't want another automobile nightmare.

Oil temp graph/Engine wear = Longevity?
 

Is the reference graph results for a 2009 370Z or 2008/09 G37 (same engine) or are you implying result from various engine makes/models tested in a somewhat overally simplistic theory?

"No one has objectively/scientifically/under controlled circumstances demonstrated when/under what conditions the engine oil temperatures rise."

I will gladly volunteer my 370Z with manual transmission as a "test 370Z". I'll even install a on-board computer so I can datalog my Z's engine temps, outside temps, engine load, engine water temp,etc. and will share the results with Nissan corporate or Nissan Motorsports. All Nissan has to do is PM me (37Z). I do not work for Nissan; however, I have owned many Nissan cars and was involved in the survey that lead to the 240SX re-design.

<link rel="File-List" href="file:///C:%5CDOCUME%7E1%5COwner%5CLOCALS%7E1%5CTemp%5Cmsoh tml1%5C01%5Cclip_filelist.xml"><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w:DontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" LatentStyleCount="156"> </w:LatentStyles> </xml><![endif]--><style> <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0pt; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:72.0pt 72.0pt 72.0pt 72.0pt; mso-header-margin:72.0pt; mso-footer-margin:0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> </style><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0pt 5.4pt 0pt 5.4pt; mso-para-margin:0pt; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} </style> <![endif]--> Wow…I’m truly sorry to hear about the problems you’ve had; then and now.

I had an ’04 Touring Coupe which I put NISMO rims on and autocrossed pretty heavily so I would have never known if I was having any tire-wear issues as I went through tires pretty easily! My next one was an ’07 Grand Touring Coupe and didn’t experience any issues with it or my ’08 Roadster either.

<o></o>Frankly I think you got a raw deal on the warranty issue but it is true than once you start modifying a car getting things covered under warranty can become a real nightmare if not knock down drag out fight…I wish it were otherwise.

I do hope your experience with you 370 ultimately turns out well.
<o></o>

The graph (I'm talking about the one on the left) isn't really specific to an oil or an engine. SAE sets standards for how oil viscosity responds to temperature, which is how we get the standardized ratings like "5W30". That chart simply states the obvious about SAE-standard oil viscosity and heat. It tells you simple truths like "A 15W40 oil running at 250F has the same viscosity as a 5W20 oil running at 190F".

If you're talking about the one on the right, it doesn't even have numbers on one of its axes, so it's clearly just a "feel good" graph trying to show the general relationship between oil temp and engine wear in the general case.

As for the rest of it, re: specifics on what it takes to damage our engine life, and by how much, we're never going to get that data. We'd need someone independent (ourselves?) to pony up several VQ37VHRs and put them on test stands in rigorous testing conditions and destroy them (and figure out the exact relationships between things like X RPMs sustained for Y seconds = Z degrees increase in oil temps). Some people in the bowels of Nissan already have this data, but as usual they don't feel like sharing.

So we do what we can with the standard things we already know about oils and engines, which leads one to believe that even without hitting limp mode at 280, sustaining 240-260-range oil temps all the time is worse for the oil and the engine wear than keeping the temps lower, and it's not hard to fix with an oil cooler.

wstar: I'll gladly datalog my 370Z and share the results with the 370Z public and Nissan as I indicated in my response. Hopefully, Nissan will take my up on this! I reside in FL and have a 370Z manual with sport package (2/09 manufacture date) with less than 2000 miles. I am looking for another 2009 370Z with automatic transmission that is willing to datalog theire Z. What's your Z specs and where does it reside?