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Engine oil

yes. And you are better off running 5w30 all the time (vs 10w).

There are going to be those foot stompers that say but Acura specs say 10w30. And their engineers.... blah, bah, blah.

5w30 will flow better when cold and be the same 30w when hot.

For the record: I run 5w40 during the summer/track and 5w30 during the rest of the year. I'm not a big one oil is better than another fan.... change it often and you can't go wrong with any synthetic.
 
yes. And you are better off running 5w30 all the time (vs 10w).

5w30 will flow better when cold and be the same 30w when hot.

I agree. I have used 5w30 for its ability to flow and to thereby minimize cold start damage for the 17 years that I have owned my '91.

As for Royal Purple, well they have a big advertising budget. It is a great Tier 2 oil, like Amzoil, and you certainly won't go wrong with it. But if you want the best - and you won't need to unless you wail on your car like I do by regularily taking it to the track and buzzing it to the redline for a good part of each session - you should use Motul or Redline oil both of which are Tier 1 synthetics.
 
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My car came with a crankcase full of Royal Purple 10w30.

I will be switching over to Red Line 5w30 next week.
 
Whose advice do you trust - Honda's engineers who designed and built your car and wrote the manuals for it, .......Keep in mind, those engineers specify using 10W30 with ambient temperatures over -2F, and 5W30 for temperatures under 36F. So if you're asking what to use in frigid winter conditions, the engineers say 5W30. But they say 10W30 is best in moderate to warm temperatures.

And 20 years ago, before advanced synthetics with their significantly higher shear strength than the then prevalent organic oil made their way into the mainstream of automotive maintenance, that was the best advice there was. :biggrin:
 
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I will be parking my NSX this winter so it will not see any cold start up's.The reasion I have a case of 5w-30 its from my RSX TYPE-S that I traded for the NSX.
 
I will be parking my NSX this winter so it will not see any cold start up's.The reasion I have a case of 5w-30 its from my RSX TYPE-S that I traded for the NSX.

A cold start up is the first start up before the engine has warmed to operating temperature. Significant wear occurs on the first start up.

Obviously if the ambient temperature is low, that is a colder, cold start up than if the ambient temperature is warm. But wear occurs during both types of start ups with, I suspect, more wear in the colder, cold start up.
 
Which advice do you trust - the manuals written by Honda's engineers who designed and built your car, or somebody posting on the internet?

Keep in mind, those engineers specify using 10W30 if the ambient temperatures are over -2F, and 5W30 for temperatures under 36F. So if you're asking what to use in frigid winter conditions, the engineers say 5W30. But they say 10W30 is best in moderate to warm temperatures.

It's up to you what to do; after all, it's your car, and you can put whatever you want into it. I want to do what's best for my cars, and I maintain them by the book. For the past 21 years, I've used only 10W30 in my NSX, which doesn't get driven in winter.

If I had an extra case of oil that I couldn't use in any other car, and I didn't want to use that viscosity, I'd just sell it (on craigslist, ebay, or one of the automotive forum websites).

And 20 years ago, before advanced synthetics with their significantly higher shear strength than the then prevalent organic oil made their way into the mainstream of automotive maintenance
That's simply not true. Advanced synthetic fluids were as much a part of the mainstream of automotive maintenance twenty years ago as they are today, with plenty of people using Mobil 1 back then, and a few spending the big bucks for Amsoil, Royal Purple, and Redline, all of which were widely available and discussed back then.

Which, BTW, has nothing to do with which viscosity of oil to use.
 
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That's simply not true. Advanced synthetic fluids were as much a part of the mainstream of automotive maintenance twenty years ago as they are today, with plenty of people using Mobil 1 back then, and a few spending the big bucks for Amsoil, Royal Purple, and Redline, all of which were widely available and discussed back then.

Why isn't it true? And why should I believe a statement about the market share of synthetics from someone's posting on the Internet? :biggrin: Show us some numbers. Right now there is nothing to show that I am right or that you are.

My recollection is that synthetics were a much smaller share of the automotive market in the late 1980s and early 1990s than they are now. And I think if you do some research, you will find that I am right. :tongue:
 
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I purchased a brand new car back in 90. until today, i keep using the same brand of motor oil. For 21 years, i've had no oil leaks. All i've needed to change has been the front seal and valve cover gasket. Another car i used all brands of oil, and after 8 years, oil leaks everywhere.:eek:
 
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Nabil over here at First Class Auto uses 5W-30 synthetic blend in NSXs that come through his shop. He's had a lot of experience with it. So I don't think you can go wrong with either 10w-30 or 5W-30.

Is it wise though to not change back and forth between the two? It's probably not wise to change back and forth between full synth and synth blend either right?
 
never switch back and forth that could be BAD LOL

its like tring a new brand of condom, it might be too big or it might be too small and you dont wanna get stuck in the middle with a perfect 10 and
not able to show her your rabbit moves. :eek:

( :edited for content ) LOL
 
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Haha ok I'll stick with 5W-30 since that is what's already in my car. I feel like because of temperature/weather I should be using 10w-30, but I don't want to switch back and forth. His goal was to I guess "wean" me into 5W-30 as he didn't know what oil my car had prior to that. So I'll just stick with it. He says he uses it all on the NSXs that come through unless they request something else so I guess it works.

But yeah, I know synth to synth blend switching can just screw it all up. I'm fine with synth blend.
 
I purchased a brand new car back in 90. until today, i keep using the same brand of motor oil. For 21 years, i've had no oil leaks. All i've needed to change has been the front seal and valve cover gasket. Another car i used all brands of oil, and after 8 years, oil leaks everywhere.:eek:

so maybe its the oil, but Im putting my bet on how well made our nsx engine is.... :wink:
 
I prefer to use the oil that Honda recommends...I know that in most cases you can go with 5w-30 and be just fine. Make sure to change your oil often and keep putting a synthetic in there and you'll be ok no matter which route you go.

This oil thing has been argued over in countless other threads, lots of heresay/facts/opinions thrown around. If you are interested in knowing a lot of what Prime's smartest (and most well researched) have to say search it and it makes for a informative read.

I currently use 10W-30 Amesoil with an OEM (short) filter for weekend and track use. FWIW
 
The cost of replacing this engine might put us in the poor house.I think I will sell the box of 5W-30 to a buddy and buy 10W-30.Thanks to all who answered this thread
 
The cost of replacing this engine might put us in the poor house.I think I will sell the box of 5W-30 to a buddy and buy 10W-30.Thanks to all who answered this thread

I honestly wouldnt be too concerned. If anything, 5w-30 would be better in your colder region. A properly operating road car engine wont shouldnt fail because of its starting oil weight under street use regardless of 5w, 10w, or 0w-30. Unless you are doing something extreme or significantly out of spec such as 20w-50, what you have is fine.

If not, Id be willing to "take that royal purple off your hands" if its such a headache:wink:
 
Well then since I'm in a hot region... should I switch back to 10w-30? Or I should I just ride out a mild winter with 5w-30 and then go to 10 in the spring?Or I can just stick with 5w-30 haha.

My car had 10w-30 all the time up until this July when Nabil put 5w-30 in it (he wasn't sure if 10w-30 was in it before that but now I know that it did after looking at the records). I'm buying my oil tomorrow morning so I just want to do it right. So basically it was a 10w-30 full synthetic before and he went with 5w-30 synthetic blend for this current interval (car has 100k miles now). I'm debating on whether I should switch back permanently or stay with the 5w-30 synth blend since that's what it's at now.
 
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5w-30 would be better in your colder region.
Only if you're planning on driving it during frigid winter weather, according to the manual. If you're going to let it sit all winter till the temperatures are above freezing, it says to stick with 10W30.

So basically it was a 10w-30 full synthetic before and he went with 5w-30 synthetic blend for this current interval (car has 100k miles now). I'm debating on whether I should switch back permanently or stay with the 5w-30 synth blend since that's what it's at now.
There's no reason you can't switch back to full synthetic, if you want the full benefits of synthetic (better resistance to breakdown when hot, better flow characteristics when cold). As for the viscosity, you can decide for yourself based on the information in this topic, in your manual, etc.
 
Well then since I'm in a hot region... should I switch back to 10w-30? Or I should I just ride out a mild winter with 5w-30 and then go to 10 in the spring?Or I can just stick with 5w-30 haha.

My car had 10w-30 all the time up until this July when Nabil put 5w-30 in it (he wasn't sure if 10w-30 was in it before that but now I know that it did after looking at the records). I'm buying my oil tomorrow morning so I just want to do it right. So basically it was a 10w-30 full synthetic before and he went with 5w-30 synthetic blend for this current interval (car has 100k miles now). I'm debating on whether I should switch back permanently or stay with the 5w-30 synth blend since that's what it's at now.
Blends are not 100% synthetic. While I don't care to get into a big debate, I agree that 5W30 and 10W30 should have the same viscosity performance as a straight 30 weight oil at operating temp (which is tested at 210*F) temps. The first # is the "Winter" rating, or cold viscosity. The 2nd number is the viscosity at 210*F.

If you have a supercharger or track your car, it might be a good idea to go with a 40 weight oil like a 0W40 or 5W40. For the case of a 5W40, it has a lower viscosity which is better at cold startups and a higher shear rating at high temps than a 10W30.

I also don't buy into the whole OEM tires, tire pressures, Oil makes, Oil weights, suspension -as the best thing out there. Look at your intended uses, understand what you're dealing with and go from there.


0.02
 
Blends are not 100% synthetic. While I don't care to get into a big debate, I agree that 5W30 and 10W30 should have the same viscosity performance as a straight 30 weight oil at operating temp (which is tested at 210*F) temps. The first # is the "Winter" rating, or cold viscosity. The 2nd number is the viscosity at 210*F.

If you have a supercharger or track your car, it might be a good idea to go with a 40 weight oil like a 0W40 or 5W40. For the case of a 5W40, it has a lower viscosity which is better at cold startups and a higher shear rating at high temps than a 10W30.

I also don't buy into the whole OEM tires, tire pressures, Oil makes, Oil weights, suspension -as the best thing out there. Look at your intended uses, understand what you're dealing with and go from there.


0.02

Billy

What do you recommend for a turbo car then if not tracking. 5w40 in the winter and 10w40 in the summer? Or still go with the 10w30? I drive in PA and plan to drive when it's freezing out.
 
Billy

What do you recommend for a turbo car then if not tracking. 5w40 in the winter and 10w40 in the summer? Or still go with the 10w30? I drive in PA and plan to drive when it's freezing out.
If it were my car, i would use M1 0W40 or Rotella T6 5W40 for cold startup and high protection as described earlier. If i wasnt going to drive the car too hard, i would use 5W30. Either way its even more important to do a proper warmup and cooldown with a turbo car. That and frequent oil changes.
 
I also don't buy into the whole OEM tires, tire pressures, Oil makes, Oil weights, suspension -as the best thing out there. Look at your intended uses, understand what you're dealing with and go from there.
+1

Honda’s engineers specified either a 5w-30 or a 10w-30 oil for NSXs. When they designed the NSX’s engine, they sized the oil pump and the oil passages to flow a certain volume of oil at a certain pressure to the bearings, camshafts, etc. given a certain viscosity (thickness) of oil. If the oil is thicker than Honda’s engineers planned, you’ll develop good oil pressure but you’ll get less flow than was calculated. If the oil is thinner than planned, you’ll get a good volume of oil but you won’t develop the pressure at the bearings that was desired.

At normal operating temperature (100° C), a 5w-30 oil, a 10w-30, a 0w-30, and even a straight 30 weight oil all have a viscosity between 9.3 and 12.5 cSt. At normal operating temperature, all of those oils will protect your engine just as Honda intended - none of them are too thin.

At lower temperatures, all of those oils get thicker than 9.3 to 12.5 cSt. They’ll all give you good oil pressure but until the engine warms up, none of them will get you the volume of flow that Honda wanted. The straight 30 weight oil will thicken up the most [edit: as the temperature drops below 100° C] and the 0w-30 oil will thicken up the least. At startup, the 0w-30 oil is the least bad for your engine.

At the other end of the spectrum, when the oil temperature goes above 100° C, as it does on the racetrack or the Autobahn, all of those oils will get thinner than 9.3 to 12.5 cSt. If you really push the engine you don’t want the oil to get too thin. [Edit: Above 100° C...] A 10w-30 oil will tend to thin out less than a 5w-30 oil, which will tend to thin out less than a 0w-30 oil (especially over time). So a 10w-30 oil will tend to give you a bigger safety cushion than a 5w-30 when you’re really pushing it.

If the ambient temperatures aren’t too low at engine startup, Honda recommends sacrificing cold flow properties for a larger high-temperature safety cushion. However, if you don’t drive your car very hard, you probably don’t need that safety cushion. In that case, a 5w-30 oil will result in less overall wear than a 10w-30 because of the better startup protection (as long as you change your oil frequently).

I have an engine oil temperature gauge in my NSX. On the Autobahn, the temperature sometimes gets close to 150° C before I slow down. At those temperatures, oils thin out a lot so I need a relatively thick oil to give me good oil pressure. I’ve found that a Mobil 1 5w-50 works well but the drawback is that at normal operating temperature (100° C) it’s thicker than Honda’s engineers wanted. As a result, it gives me very good oil pressure at 100° C but if I had a stock oil pump, it wouldn’t give me as much flow to the bearings as Honda’s engineers wanted.

In summary, if you’re not going to drive the car very hard, I wouldn’t worry about putting a 5w-30 oil in it regardless what the ambient temperatures are. If you drive the car hard, a 10w-30 or perhaps an even thicker oil may be better, as stuntman mentioned. If you follow the recommendations in the Owner’s Manual and change your oil frequently, you’ll be fine. But if you think through how you use your car and what viscosity ratings mean, you may be able to find an even better oil for your car than the blanket recommendations given in the Owner’s Manual.
 
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