From 10W40 to 0W30
 

Hi all,
Changed the oil of my wife's car (little, French Renault Twingo 1.2 '08). There was 10W40 on it and I shifted to fuelsaving 0W30 (allowed according to manufacturer).
The result should be noticable as this car is:
- always parked outside (so cold)
- driven for approx. 2 to 3 miles/drivecycle
Anybody did a comparable change and noticed any difference?
I will keep you posted if I see any difference, but this will take maybe two months (wife doesn't drive often and as I drove this car today for a long trip the fuel consumption will have dropped for this tank).

Which brand of 0W30 did you use?

The original Honda branded oil, same as for e.g. Civic Type R.

I've found that there is a small difference between oil viscosities, however I usually drive older cars and sometimes I'll hear/notice a difference when I use a light oil.

-Bob C.

I didn't know that there is Honda-branded oil, but I guess that makes sense...I think most major manufacturers sell their own brand of oil too. How does the price compare to major independent oil brands? In the US I would expect to pay significantly more, but I don't know if the same price issues exist elsewhere.

I used this 0W30 in my VW:
https://lh3.ggpht.com/_oNsRR_T1Qx0/ST...0/IMGA0390.JPG
(Castrol Syntec European Formula 0W30)

Oh yes there is Honda branded oil with a Honda partnumber, I think also in the States, but not all manufacturers sell own branded oil. The Honda one is from a Japanese manufacturer. Forgot the (difficult) name.
To be honest, I didn't compare prices as I could get this oil very cheap. But you're right: normal price at dealership is 76 euro for 4 1-liter bottles (= very expensive).
In my previous Honda motorcycle I also used Castrol.
For my current MCycle I use the original branded Honda motorcycle oil (10W30) for same reasons as the 0W30 (reduction).

I think everything I own can be classified as an "older vehicle". I use 0w30 in my 98 GMC, but I use 5w30 in my 81 Buick, and 10w30 in my 86 Chevy. The engine in the 86 Chevy just isn't in that good of shape anymore, and a slightly thicker oil probably does it some good. I'll probably switch the Buick to 0w30 on the next oil change, haven't yet decided for sure though.

Hi Jay,
A problem when using 0W30 when it's not allowed by manufacturer can be the flow of the oil pump. You should be sure it can still give enough pressure on low revs with the thin oil.
If this is fine, then thinner oil is always better for lubrication than a thicker oil.
If you lose oilpressure somewhere in the oilpath because of thinner oil, than your engine is really worn out.
With thinner oil you can have a bit more oilconsumption, but at least there is oil between the metal parts. With thicker oil it will take longer before there's lubrication on the most far away points.
Also interesting: switching from 5W30 to 0W30 changes nothing when your oil is hot. It can only be good for your engine.

Exactly. My 86 Chevy already comsumes a lot of oil through various drips here and there. I didn't want to make it worse with a thinner oil.

My understanding was the opposite, that thicker oil is more difficult to pump but in a worn engine with larger clearances the thicker oil would be better lubrication...while thinner oil is easier to pump everywhere quicker, and gets into tighter clearances better.

Hi Holy cow,
This all depends on the manufacturer of the engine. If 0W20 is allowed, this means that with this oil in all circumstances there will be enough pressure left.
My Civic can take 0W20 and at next oil change I will put it in.
Pay attention to what you call a 'worn engine'. In my understanding that's an engine where the clearance between pistons and cylinders is to big. If in your understanding a worn engine is one where the clearances in the bearings are bigger, that's another story. You should find out where pressure is lost.

I don't see how worn cylinders will affect oil pressure. The blowby might affect crankcase pressure, and more oil might be burned, but the pistons do not receive directly-fed oil as far as I know...

-BC

Oh no Bob, I didn't mean you will loose pressure when pistons/cylinders are worn.
I meant that you will consume some oil with thinner oil when pistons/cylinders are worn, because the bottom oil piston ring will not be able to do his work anymore.

That's right... Thicker oil is more difficult to pump through small openings so you end up with more pressure than the same engine running a thinner oil. As bearings open up pressure with the same viscosity will fall.

The difference between 0 and 10 will be almost nothing as far as engine protection is concerned although you may notice a performance increase. You're talking about when the engine is cold and even 0 weight is thicker in a cold engine than 50 weight in a hot engine. I noticed it in the Tracker but am pretty sure I wouldn't in the Durango as I don't even notice the AC cycling in that thing.

Well, Jones, I picked the '0WX' because with lower cold resistance the oil will always be pumped quicker around the entire engine than a '10WX'-oil. That's where the difference in protection should be, especially with this car that's always driven cold. In these circumstances there's a risk that the (OH-)camshaft receives very late or insufficient lubrication time after time.
Her previous car started consuming some oil after approx. 50Kmiles, same bad circumstances. Now that the warranty period is over I can put in it what I want: only the best for our conditions, within the manufacturers margin. I don't want this car to see consuming oil so quick.

A good anti-drainback valve should prevent the oil from draining out of the passages. Since you have an OHC engine I can see it being more of an issue.

The viscosity of oil is the HIGHER NUMBER so a 0W-30 has the same viscosity of a 10W-30. It is not thinner. The "W" stands for "Winter" to signify how it flows at lower temps.

20W good to 32 degrees F
15W good to 14 degrees F
5W good to 0 degrees F
0W good below 0 degrees F

(degrees from memory, but you get the idea)

Thickness is approximately the same as viscosity in these discussions.

As for the ratings...It's multi-viscosity. The number before the W is its viscosity rating in low temperatures. The number after the W is its viscosity rating once it's warmed up.

I could go on, but here's a link where somebody wrote it accurately and succinctly:
https://www.repairfaq.org/filipg/AUTO/F_oil_facts.html

Both numbers are a measure of viscosity, or at least a standard labeling system corresponding to viscosity. Manufacturers should post actual measurements for viscosity under product specs. THC's Castrol falls in the 30 range, but is at the high end, close to 40.

Apparently, 'cold' viscosity testing is done at 40C. For the Celsius challenged, that's 104F. Publish results for Mobil1 10w30, 5w30, and 0w30 are really close, but I wonder how much they'll diverge under real world cold temps.

I've heard that 0w isn't possible with dino oil. So, if you want a true group IV synthetic, or least higher percentage of it, grab the 0w.

Yes Darby, thanks, but nobody ever doubted this? I can only confirm.

my take is that you can't go wrong w/ 0W30 or 0W40, whichever app is "recommended"(in regard to 30 or 40 weight). i have also heard that 0W20 should be avoided except under fully cold climates. obviously one could use it in the winter of moderate climates, and switch to 30 weight the rest of the year.

20 weight, as it was told, was to help manufacturers reach economy requirements by the govt, no?

Hi Bowtie, I agree that you can not go wrong with the weight for hot. But I changed to 0W30 because of the 10 to 0 switch, not because of the 40->30.
0W20: In Europe Honda has now already 2 types of 0W20 on the market (Honda branded). One 'regular' and one especially for their hybrids. The hybrid one is even a bit thinner than the regular! They don't try to 'hide' or disapprove this oil in Europe. Of course, the fuel consumption advantage you have with 0W20 is important for the FE-ratings.
You can not use 0W20 in engines that are not approved to use it (tolerances, especially of the oil pump are main factors to keep the flow and pressure high enough in all circumstances).
But it's an tendency that can not be stopped. 10-15 years ago 0W30 was kind of 'exotic', now it's common.

I've heard this, and may be part of the reason, but Ford has back certified many of their vehicles/engines for 20 weight. Doing so wouldn't affect new cars reaching requirements.

Of course, it may have been in consideration of dealer overhead and storage space.

I switched from 5w-30 to 0w-30 a few weeks back. When i start the car cold, the RPM jump up about 200 higher than with the thicker stuff, and after the switch the car was noticeably more "zippy" before warmed up.

It's too early to tell anything about fuel economy, but
- The engine sound when cold is much 'smoother' and she seems to run a bit more stable.
- Reaction on throttle when moving of cold the first kilometers is also according to me more agile.

First fill up after new oil
 

Filled up today first time after 0W30. Only 4/5 of this tank was with the 0W30.
Reminder: this is not about the Civic, but the small Renault 1.2 petrol of my wife.
Positive result:
- less consumption than two last fill ups, but now it's freezing
- less consumption than February till September fill ups from last year (! strong, isn't it?)
- same consumption as the period May -> June of this year, but than it was much warmer
We only consumed less than last fill up in specific circumstances: sometimes I used this small car for daily commute before I owned the Civic. Only in these periodes we see less consumption.
3 days ago I also made a grill block for the Renault, but only a 50% to take no risk at all as it's my wife who's driving and I have no diagnostic tool for this car to measure temps.