Engine Oil options

[mutley]

Hi all,

Just curious to ask what is everyone’s engine oil of choice these days. I know the recommendations is 10w30 or 5w30.

Anyone know what is the best to use (which brand etc)

Cheers
Jim

[NZNick]

I use the Honda FEO 10W-30 API SN that the local dealer uses:

14578 14579

Some googling reveals that this is made by Castrol for Honda in the Australia and New Zealand markets, to the same specification as is used at Honda's Japanese dealer network.

[Kaz-kzukNA1]

Hi, Jim.

I normally won't post on the subject of 'Eng Oil' as there is no such thing as 'best one' without knowing the eng design spec, fuel in use, track/road simulation data, driving environment, etc.

But as I know who you are and always want to help someone looking after the country, here is what I know.

First, just get the eng oil from the major oil company close to the OEM viscosity spec of 10W-30 or 5W-40.

I use Mobil 1 0W-40 for my NSX and changes the oil+filter twice a year, normally in spring and autumn as mine is a daily driver although not to be the case since beginning of 2020.

Over the last 28 years with more than 167,000miles, pretty much always stayed with the Mobil 1 in Japan and UK although the formula would be changed over the years.

If not driving regularly, changing the oil annually would be a good measure.


Being as the production car manufacture, Honda won't design the engine that requires special eng oil that is hard to get hold of in remote island.

Thus, the above recommendation of just get the well known one close to the OEM viscosity.


There were exceptions such as Nissan GT-R engine VR38DETT.

When introduced on the market, to keep the manufacture warranty, the owners had to have their oil changed using the specified eng oil 'Mobil 1 for GT-R'.

This condition was dropped long time ago but still many owners in Japan carry on using the Mobil 1 0W-40 with the small print stating 'Meets the requirements of Nissan GT-R'.

This small print was removed in Japan when the manufacturing site was changed in Japan but still the same formula.

Mobil had to re-apply for the 'approved by the manufacture' status in Japan to Nissan but so far, haven't seen the logo on the latest Mobil 1 sold there.

For the clarification, the eng oil spec in one country doesn't mean the same for the other.

So Mobil 1 0W-40 in Japan (known as the gold can) is not the same as the Mobil 1 0W-40 New Life in UK.

However, Exxon Mobile states in their product data sheet in UK that 'it meets or exceeds the requirements of Nissan GT-R'.


During the NSX development stage, all sorts of endurance tests were carried out but just less than 1 year to go before the production, the engine design had to be changed dramatically.

This was due to the strong marketing opinion from US so significant safety margins were introduced as there was just no way carrying out the same amount of endurance tests well before going into the production.

DOHC, VTEC, titanium conrod, etc were all introduced after the decision of design change.

Despite all these changes including the higher rpm band, the eng oil requirement spec didn't change.


Don't be fooled by the youtuber comparing the eng oil by scratching two metal pieces and showing all sorts of temperature, marking, etc video.

Even some of them go into the chemical material number/percentage stating one oil is better than the other.

Eng oil doesn't work like that and the lubrication is just one feature of it with lots of other features to be considered.


In Japan, Honda uses its own branded eng oil manufactured by oil companies.

For NSX, the recommendation started with Honda Ultra LTD oil 10W-30 or API SG class/above or ILSAC certification marked oil.

With the advancement of engine design, manufacturing process, etc in other Honda models as well as other makes/models and the eng oil technology itself has advanced that the OEM oil has also improved.

Addition to the Ultra LTD, Ultra Limited SH 10W-30 was introduced in the mid '90s.

In early '00s, because the OEM oil changed so the recommendation for the NSX also followed it.

Ultra LTD SL 5W-30, Ultra GOLD SL 5W-40, Ultra MILD SL 10W-30 or API SJ class/above or ILSAC certification marked oil.

And the latest is Ultra LTD SP 5W-30 and Ultra MILD SP 10W-30.

Ultra GOLD went on to SN class 5W-40 but not many engines were specified for its use so when other OEM oil took SP class, it was discontinued.

Shame as it was one of the favourite for the VTEC mechanism.


With the introduction of hybrid engines and even higher demands for the fuel efficiency, there are now many eng oil specifically designed and engineered for these modern engines.

In Japan, they are sold under the name such as Honda Ultra Next, Green and Leo and clearly states that these oil can be used only for the specific models.

Therefore, just be careful not to use them on our NSX.


Kaz

[mutley]

Hi Kaz,

Thank you for your extensive reply, as always you are the font of all knowledge on matters of the NSX (I am looking forward to you seeing my car and your opinions since the last time you saw it).
The reasons I asked the question, was that I was finding it quite difficult to locate 10W 30 , as it as the brands I looked at with that viscosity were labelled for harder tools and motorbikes!

But now that I see 5W-40 is readily available I think I will go for that .

Thanks again,
Jim

[Kaz-kzukNA1]

Don't know the latest but Honda UK dealers were using the oil from Castrol for years including for NSX so that'll be a good option as well.

Kaz

[josensx]

Buenas tardes, Kaz no consumirá más aceite con el 0w40 en comparación con el 5w40?

[josensx]

Good afternoon Kaz will not consume more oil with the 0w40 compared to the 5w40

[Kaz-kzukNA1]

Depends on so many factors as per my post #3.

If talking about our NSX engine, with no modifications to it, normal street driving usage, fuel that meets the UK/EU quality requirement, etc, I would be surprised if you can tell the oil consumption difference between different oil viscosity.

I can't.


In fact, under normal driving conditions and usage on NSX engine, if you can see that the oil level has dropped noticeably before your next oil change, I would be worried.


I normally check the oil level 5min after stopping the engine and never noticed even a tiny drop after few thousands miles when I used to do 10K miles per annum but changing oil in spring and autumn.

Over the last 2 years, not doing enough mileage but still keeping the same habit of changing oil twice a year so can't tell anything about the oil consumption.

Already covered more than 165K miles, aware of oil seepage from the valve stem seal but no change in oil level.

Taking engine compression at least once a year for 28 years and no significant change on any of the data for all six cyl.


You better ask the same question to some of the AP1 S2000 owners especially the early model ones.

Some are most likely using the same oil as ours.

You will be surprised how much oil they are burning before the next oil change.


Kaz

[josensx]

Good morning Kaz, I understand that your recommendation for my Nsx'91 with 25,000 miles is Mobil1 (0w40)? Thanks a hug 🤗