oil viscosity for winter

[rys2kmk]

I recall seeing a thread some time ago that Honda's recommendation for winter changed from what is in the manual. Maybe I'm lame at searching, but I couldn't find the thread.
FTW, I'm talking about Minnesota winter... so temps below zero will be expected :D

So the manual (for my '07 AP2) recommends 5W-40 for below zero vs. 10W-30. If memory serves, the thread I saw discussed 10W-30 as the recommendation no matter what.

Is this the case? Thanks!

[bimdub]

10W-30 is the preferred on my 02.

[thereur]

If you want better flow at low temps, go with a 5W30 year round. Best of both.

Also: http://forums.s2kca.com/showthread.php?t=17598

[The Mangonel]

My Camry runs 0W20, now that's thin! However, I run 5W30 year around in the S.

[repiv]

My winter temps are somewhat similar to yours, perhaps a bit colder. We can get as low as -39, but we can get -35 fairly consistently for several days running. I've been going with a 5W30 full synthetic for winter and then I switch back to 10W30 once the daytime temps stay hot. I basically do 2 oil changes a year unless I've got a long road trip in there.
There are many reports of S2000 owners going with 0W30 when they can find it. The only problem with this is that your oil pressure may run alarmingly low during extended operating periods on the warmer days.
I tried 5W40 year round a year ago but found the oil pressure to be less desirable than using 2 different viscosities for the opposite seasons. In summer, the pressure dropped a bit lower than I'd like and in winter, the pressure after a cold start was scary high (close to 100 psi). But that's just me. If Honda says 5W40 year round, then it should be fine.

[thereur]

There are many reports of S2000 owners going with 0W30 when they can find it. The only problem with this is that your oil pressure may run alarmingly low during extended operating periods on the warmer days.


Can you expand a bit on this? If I compare specs on say Amsoil 0W30 and 10W30, the viscosity difference at 40C is not much. Surprised you'd see such difference between a 10 and 5.

[repiv]

Can you expand a bit on this? If I compare specs on say Amsoil 0W30 and 10W30, the viscosity difference at 40C is not much. Surprised you'd see such difference between a 10 and 5.
40C is just over body temp. This can be considered fairly "cool" for oil. Where we see the differences are at temperature extremes and this happens once we run the engine for extended periods of time (long after full warm up is reached). Oil temps can get above 115C (240F) even in the middle of winter if it's a warm day and we've been stuck in stop and go traffic for a long time. It is at idle in such conditions that oil pressure can drop quite low. I don't know what viscosity changes there may be for oil above 115C+ but I know it does make a difference to the amount of resistance to pumping and that's what we see as oil pressure and there have been reports of the oil light "flickering" during hot idle when using certain 5W30 and 0W30 synthetics. I see it as a significant difference in oil pressure, even though I've never had my oil light flicker. I can also see the difference in oil pressure on extreme cold starts. Pressure can be between 5 and 10 psi higher with 5W40 as it is with 5W30 on very cold mornings (-30C and colder). However, when we are already dealing with oil pressures in excess of 90 psi on a cold start, 95 to 98 isn't really that much different. However, on hot idle, the difference between 15 psi and 20 psi may make the difference between seeing the flicker and not seeing it when the idle takes a dip. Not that this concerns me but, those who have had the "idle stumble" that I've written about and don't understand why the light flickers sometimes, seem to be quite disturbed by it.
PS. I consider Amsoil to be one of the oils at the top of the heap and is likely far more stable in viscosity over temp changes. I guess that's part of what you pay for. Those who have reported peculiarities with oil light flickers have been using Mobil 1 or other brands that may not be so stable in temp extremes. This is not saying that M1 is a bad product, but it has become apparent that it is no longer as high up the totem pole as it once was.
PPS. My above statement is not an endorsement of Amsoil, just a guess of what might be a specific trait of it.

[thereur]

That's interesting. Being in Caiif I can run anything (0-10W). I've got the German Castrol 0W30 in right now. This makes me want to get an oil gauge. Hmmmmm.

As always, thanks for your thorough reply!

[repiv]

I've got the German Castrol 0W30 in right now.
I have heard very good things about this oil. Just watch for any light flicker on hot idles.

[SpitfireS]

German Castrol 0W-30 is close to being a 40 weight at 12.x cSt @100C.
It is still a good oil though.

IMO, if one sees the oil light flicker during a hot idle, one may have a problem somewhere.
It might be the pump, or "worn" bearings or something else.
I very much doubt its the oil.
Most Used Oil Analysis I've seen on dino 10W-30 oil show they shear down into a 20 weight, IOW: below 9 cSt @ 100C.
Even then, during a hot idle, the oil light should stay off.
The manual specs 36 psi at idle with oil at 80C.
For arguments sake I'll say that's with a 30 weight oil.
The manual does not spec the psi at which the switch should be made, they just say: when the engine is running.

Dave: have you seen those oil temps and pressures yourself?
(not necessarily in your car)

I've used a 0W-30 at a trackday on S-02's and never seen the oil light come on.
A UOA showed that oil was still 10.x cSt, after 19k km. including that track day.
It wasn't your average "synthetic" oil, that is true.

And yes, I did also ruin an engine using 0W-30, but that had to do with the A048 R-compound tires.
They gave me much higher cornering speed, one specific corner was a long and tightning right hander and it was there, in that corner, where the engine held back, as if it ran out of fuel.
In the pit area I had the oil light during idle, bye bye engine.

Back to the original question:
Honda recommends 5W-40 for lower outside temps because of the 5W, no doubt in my mind about that.
In 1999, the 5W-30 oils on the market were not that good, sheared down a lot, etc.
I've been reading about that on BITOG.
Now, in 2009, the 5W-30 and 0W-30 oils are a lot better, especially the true syn oils.
They hold their viscosity, IOW they stay-in-grade and can take the heat.

There is no mechanical drawback whatsoever using a syn 0W-30 yearround, anywhere.
(*) After all: at operating temp it IS a 30 weight, just as the 5W-30 and 10W-30.
Don't forget that.
Above operating temp the true syn oils can take the heat and the stronger base oils will protect the engine better.

Remember that Honda called back the MY00-01 (IIRC) European S2000's to get the oil jet bolts replaced, to make sure there was enough oil flow reaching the pistons at sustained high speed.
That's all they did, Honda never recommended anything else for "summer" oil than a (*) 30 weight.
IMO Honda never took the time or effort to change the manual when it came to any type of oil, engine, trans or diff oil.
10W-30, MTF and SAE 90 GL-5.
It's been like that since 1999.

10W-30 is not obsolete, but there are better cold flow oils available, like (depending on the outside temp) 5W-30 and 0W-30.
MTF is still in use, no problems there.
SAE 90 GL-5 for the diff has also created a lot of debate and I don't feel like going into that now as that will take another page or 2 to explain ;)

I'm using Amsoil SSO 0W-30.

:yo:

[repiv]

Dave: have you seen those oil temps and pressures yourself?
(not necessarily in your car)
Oil temps, only from what others have said and posted. I have an oil pressure gauge, so those are my own observations.

[SpitfireS]

Oil temps, only from what others have said and posted. I have an oil pressure gauge, so those are my own observations.
What was the lowest oil pressure you have seen?

[repiv]

What was the lowest oil pressure you have seen?
Just over 10 psi. There are no finer graduations so can't tell exactly what it was.

[SpitfireS]

Compared to 36, 10 is pretty low.
Even if it was 15.

Spec'd is 36 psi with 80C oil @ idle revs.
Was the oil you were using hot at the time, as in: over 100C?
Did you see the low oil pressure warning light come on with that pressure?

Here's a link to a post about hot oil temps on the track.
110-125C (230-257F) is not uncommon and doesn't seem to do any damage.
http://www.s2ki.com/forums/index.php?showtopic=705376&st=0
(yes.. I've posted in it, that's why I remembered this post)

Another thing to think about: the HTHS of an oil is measured at 150C.
HTHS = High Temp ;) High Shear.
Oil can reach that temp easily when it gets sprayed at the pistons, or, much more important, when it has to keep the main crankshaft bearing parts apart, IOW maintain the oil film.
Some oils are even designed to temporarily shear down to reduce hydrodynamic drag in those bearings to lower fuel consumption.
There have been posts about 5W (or 0W)-20 oil used in an S2000 in Las Vegas (area).
UOA's were normal.

:hello:

[repiv]

Spec'd is 36 psi with 80C oil @ idle revs.
Was the oil you were using hot at the time, as in: over 100C?
Did you see the low oil pressure warning light come on with that pressure?
Since I don't have an oil temp gauge, I can't say what it was at any given time. All I can tell you is coolant temp, which is only a very vague indicator of oil temp. Usually oil temps lag behind coolant temps as the engine is in the warming up stage and then once the coolant reaches its stable, full operating temp (where the thermostat has opened), oil temps will have caught up and then exceed coolant temps (from experience with other cars).
My observations of the low oil pressures have always been long after coolant temps have reached full operating (95C to 100C) and the rad fan has cycled on several times. I have never seen 36 psi on hot idle, even after just reaching full operating coolant temps. 25 psi is fairly normal for me until the engine has been running for some time, then it goes down to <20 psi, with the occasional dip to <15 on the rare times when the idle takes a slight dip to 400 rpm. These are when the ambient temps are very hot and I get too premature in pushing the clutch in when coming to a stop (see my stuttering idle and near death thread). At no time has my light ever flickered.
PS. This is with an Autometer needle type gauge with an electronic sending unit. I have replaced the sending unit once since the original one began to leak some years after installation. Pressures given by the new sender is consistent with the old one. I first put in the pressure gauge when the car was only 2 years old.

[SpitfireS]

Is there anybody that thought: "You know, I learned something today."
?

[thereur]

Is there anybody that thought: "You know, I learned something today."
?

elke daag :) - but don't assume my written Dutch goes much beyond that.

[SpitfireS]

elke daag :) - but don't assume my written Dutch goes much beyond that.
Haha :thumbup: , not bad :rofl:
(it should be "dag")

Anyway..
I did not mean in general but reading this oil topic.
:poke: :lol3:
In general I can also say I'm still learning almost every day.
What I learned posting this reply - well.. not this one but the one before this one - is that there is no picture of the Southpark bunch (Stan, Kyle, Cartman, Kenny) with the words "You know, I learned something today".

:yo:

[repiv]

Only a fool says he doesn't learn new things anymore. I've learned lots of stuff here and Spitfire has been responsible for some of those. :thumbup:

[NeuterdSputniks]

Actually, I learned a little bit reading the thread.

For the past 2 months, I've been a bit worried about my oil pressure (ever since I installed the gauge - PLX).

I've seen the exact same indications that XV has seen: 10-13psi after the car's been running for awhile, 80-90psi cold start depending on outside weather, 25-30 initial idle dropping to 20 as the engine reaches operating temp.

I have seen the oil pressure dummy light flash when I let the idle dip too low, but then the PLX sending unit has a higher threshold for the dummy light than stock (7-9psi vs 3-4psi).

Currently I run Valvoline Conventional 5w30, thinking about moving to Amsoil but not sure what viscosity I want to run yet...(leaning towards 5w40).