You don't say where you live as in I drive in -20 weather or like me drive in temps over 30. If my S2000 used a lot of oil I'd use 15/40 oil and see how that does.

ROD

 

Oh seasons don't exist in Miami Florida, I'd run a 5 or 0 if it got colder than 40 degrees, it almost never does here. And if it does, I just park it in the sun with the hood up and let the sun do it's thing.

 

40 degrees, a 15/40 is good down to -15. My mix of oil in my S works out to a heavy 10/40 and My S has seen -7 degrees once but it sees some teens and 20's for some of the winter. I don't have to add any oil in my 7500 mile runs, summer or winter. I have a little over 130k miles on my '06 and its a year round driven car(just not in snow) with air temps from the teen's to 122. Even with it 122 and the ac on the car didn't over heat with the stock radiator, June is not a good time to go to a wedding in Palm Springs.LOL

ROD

 

Yes. The first number W is the viscosity at a specified ambient temp. The lower the number, the less viscous (not as thick) it is. That means it is thinner at starting and may give better lubrication on start. (Synthetic better than dino from left over film) The second number is what the oil is at operating temp. All 30 oils are the same viscosity at op temp. Once running at operating temp, there is no difference, in viscosity, between a 0W-30, 5W-30, or 10W-30.

Other than start up, once an engine is at operating temp, it does not matter if it is summer or winter outside. The engine will maintain a certain temp, all things remaining equal, as far as the oil is concerned and will be at the viscosity it is formulated for. (Not talking about racing.)

 

There's a little more to it then just having different viscosity at different ambient temps. I have read that you want the smallest spread as possible. So running the the highest W you can with your start up temps, And the lowest operating temp viscosity you think you should run with how it's driven blah, blah. Will help with mileage and yada yada efficiency all while staying within the Service Manuals range.

Getting an oil to flow effectively the "same" at to far extreme ends of the spectrum (temp) is pretty mind boggling to me. those 0W-30's or even 40's have a ton of additives.

Still most would say follow the SM or pick wisely if u have added a force multiplier like SC FI.

 

Synthetic oils don't need as many...or sometimes any additives to get a large viscosity spread.

More additives make oils more prone to shearing. Once the additives wear off, the oil will be thicker at start up, and thinner at opetating temp.

S2000's shear oil apart. That's likely why Honda went with a 10W30 spec. CONVENTIONAL 10W30 is more shear stable than CONVENTIONAL 5W30. Honda did not spec a synthetic oil for S2000's.

They spec'd a 5W40 for arctic use, however. Which, almost inherently means synthetic. You'd be hard pressed to find a conventional 5W40.

Synthetic 0W30 should be more resistant to shear than conventional 10W30 or 10W40.

 

This. The rule about low spread between W number and higher number was true for conventional oils. It meant the oil wouldn't break down as quickly and lose all its viscosity numbers. Not really an issue for full synthetic (real full synthetic).

 

Yes, but think about average Jane and John Doe, that never checks their oil. They are in more danger from low oil ruining their day than a little extra wear on every cold start on a cold day.

IMO, these 3k mile oci recommendations that are sometimes pushed on average citizens are not such a bad thing, since that ensures their oil never gets too low, as there is zero chance they will ever top it off themselves.

 

Speaking of checking, I've gone through about a 1/3rd of the bottle in 600 miles. Before I'd just be putting in about 70% of the bottle by now, then the rest of it by ~820 miles, before having to add again at 1,000 miles. So for me this oil is a win, and I don't know if this matters at all but the oil has stayed clearer than usual. By now the oil would start turning brown and easy to read on the dip stick, but it's still pretty golden FWIW.

 

Thats not true in any of my bikes, they will kill a 5/40 in around 1800 to 2200 miles. But when I run the conventional 15/40 oil it will last for 3500 to 4000 miles. If the S2000's shear oil apart as some say on here then use a shear stable oil. I run a mix of oil in my '06 4qt's M1 5/30 H/M and 2 qt's M1 V-Twin 20/50, that makes it a 10/40 with a very strong anti-wear package. Been doing this for 100k miles on my S and I like my UOA's that I've run.

But If my S used a lot of oil I would bump it up to a 15/40. One more thing you can do is when you have to add oil put in straight 40w oil, most 40w oils have a very strong anti-wear formula and if the S does shear oil quickly then the 40w will bring up the cSt to a better number.

ROD