I just got done reading a post about someones engine being damaged and they suspect its from using 0W-30 / 0W-40 oil in their crankcase. Could using this kind of oil really damage an engine?
Will a oW-XX hurt my engine?
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Patman
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It definitely won't damage your engine. There is a common misconception that 0w30 and 0w40 oils are too thin, but if you look at their viscosity at 100c, you'll notice that in many cases they are actually a bit thicker at operating temperature than other 10w30 and 10w40 oils.
100C being the operating temp. The 0w part only refers to how the oil behaves when cold. W=Winter. It will however always get thicker as the temp lowers below 100C. It just doesn't thicken as quickly or as much as a 5w or 10w. It is never thinner than a 30W at operating temp. It seems every 0W 30 does a good job as they are all synthetic higher priced oils by premium manufacturers and should protect better in cold weather and no worse when warm.
I've also read several posts on various forums where someone is claiming that an 0W-xx oil damaged their engine. However, when questioned by other members of those forums it usually becomes aparent that what's actually happened is that the engine concerned has been running on dino oil for many years/tens-of-thousands of miles and has some sludge or deposits in it. The 'thin' 0W-xx oil, almost certainly a synthetic with a good additive pack, is then very good (or bad depending on your point of view) at dislodging these deposits which then clog filters and oil-ways etc, leading to problems/damage.
Yes, if they've never changed it.
As others said, at operating temp, a 0w-30 oil will be as thick (or as thin if you'd like) as a 10w-30 oil. And that is the thinnest it'll normally get. At lower temps, it can only be thicker.
I did get a better UOA on my Ranger with M1 5w-30 than the 0w-30, not that the 0w was terrible.
LINK PLEASE.
JHZR2
Staff member
Noticed the same thig in my mother's plymouth breeze, using 5w-30 over 0w-30. I think the differece is that on the way from -35 or whatever it is, on the way to the typically studies points of 40C and 100C, the 0w-30 oil has to thicken up at a faster rate than the 5w-30. Because of this, at typical points, seemingly cold to us, say 32f, or even 0F, the 5w-30 may actually be thinner than the 0w-30. This wil effect flow and startup wear.
JMH
Well all I can say is that there was a difference from the Delvac 1 5W-40 and the Esso XD-3 OW-40 this winter at cold start-ups.The OW oil wouldn't lag my oil pressure gauge as much as the Delvac 1...sometimes to the point where the "check gauges" alarm would beep...only happened once with the 0W Esso as compared to almost daily with the Delvac...same oil filter (Wix).
JHZR2, I think you have it backwards. The oils thin as they warm up. A 0w-30 would have to thin up less than an 5w-30. I believe that a 0w-60 oil is one that essentially not thin at all between room temp and 100 deg C, this was mentioned on this board once with respect to Shell Ultra Helix.
A 10w-30 is thicker than a 5w 0r 0w-30 when cold, and would therefore have to thin more than either a 5w or 0w-30 to become a 30wt when hot.
Feel free to correct me if I'm wrong
A 10w-30 is thicker than a 5w 0r 0w-30 when cold, and would therefore have to thin more than either a 5w or 0w-30 to become a 30wt when hot.
Feel free to correct me if I'm wrong
What's cold (as in a cold start)? Freezing, sub-freezing, room temp, desert heat?
Apparently "German Castrol" 0W-30 is thicker at 40ºC than most 10W-30 oils. However - at that temp almost any oil will be relatively thin and should flow quickly.
A multigrade oil only has viscosity requirements at two sample points. The viscosities in between can vary by a bunch.
http://www.finalube.com/reference_material/SAE_Viscosity_Grades_For_Engine_Oils.htm
With the higher viscosity index a 0w oil has to thin as it warms on a less steep slopIt is designed to crank at -35°c on the way up to 100°c it does not thin as fast at 40°c the oil can be thicker with a 0w than with a 10w.
This is the problem with the current oil grading system. It doesn't tell how thick an oil really is and is therefore almost useless to the average consumer other than following recommendations in the owner's manual. I mean M1 5w40 is thicker than M1 10w30 at 40C. How many consumers know that? Better yet I still haven't heard a single good explanations of what 0w, 5w or 10w means in hard numbers other than one being thicker than the other. The only way to properly show viscosity would be a cSt vs temp chart from pour point to flash point. Not 2 data points from which we extrapolate a VI. Who does that?
Show us the graph on the back of the bottle.
Check that Finalube link. It has the exact definition of 5W/10W/15W/20W/25W cold cranking and cold pumping viscosities.quote:
Originally posted by jtantare:
This is the problem with the current oil grading system. It doesn't tell how thick an oil really is and is therefore almost useless to the average consumer other than following recommendations in the owner's manual. I mean M1 5w40 is thicker than M1 10w30 at 40C. How many consumers know that? Better yet I still haven't heard a single good explanations of what 0w, 5w or 10w means in hard numbers other than one being thicker than the other. The only way to properly show viscosity would be a cSt vs temp chart from pour point to flash point. Not 2 data points from which we extrapolate a VI. Who does that?
Show us the graph on the back of the bottle.
And it's actually three sample points, but the two cold weather ones are extremely close to each other and describe different things.
BTW - the GM 6094M cold pumping spec is more stringent than SAE J300:
http://www.imakenews.com/flashpoint/e_article000098450.cfm
The Finalube link explains the current definitions behind 5WX, 10WX, etc.
If you'd like to know the historical definition, which is distinct from the current one but nonetheless amusing trivia, this site has an explanation:
http://www.synlube.com/sae5w-20.htm
Note that the site I just linked to also has the dubious honor of marketing the most expensive passenger car motor oil on the freaking planet.
If you'd like to know the historical definition, which is distinct from the current one but nonetheless amusing trivia, this site has an explanation:
http://www.synlube.com/sae5w-20.htm
Note that the site I just linked to also has the dubious honor of marketing the most expensive passenger car motor oil on the freaking planet.
JHZR2
Staff member
Right, thats exactly what I meant - just not phrased clearly I guess
And its as true at 40C as it is at 0C. Cold for us, but indifferent for an engine. Well above the cranking test spec for a 0w- or 5w- oil. Therefore, the 5w- oil can be thnner than the 0w- at temperatures of 0c, even -10 or -15C.
JMH
But it probably isn't and even if it were they sure would be close. Not the sort of thing that blows motors. If your comparing the cold aspects of different 100c viscosities even if there both considered say 40w, the curves may cross somewhere. This is kind of immaterial to the original question regarding actual engine damage. All the 0Ws are synth and are thinner when cold than their 10w counterparts at all temps unless they're originally thicker at 100c in which case the curves will cross somewhere. Castrol 0w30 will be thicker than M1 5w30 at most temps because the green is closer to the 40w and M1 is closer to the 20w side of 30 at full temp. The castrol visc. curve will also cross the M1 10w30 somewhere because it ends up thicker. I'm sure the curves aren't perfectly linear but I'm also sure that they're pretty predictable especially with synthetics(0w).
I believe that if large amounts of VI improvers and pour point depressents are used, there might be non-linear changes in the viscosity/temp graph. There seems to be many ways to make an oil that conforms to SAE 5W-30, and their viscosity plots can vary accordingly.
BTW - I've heard from one person that an ideal might be a straight 30 weight oil along with a block heater warmed up before starting a car. Of course a problem would be where to plug it in on the road. It probably wouldn't meet the EC spec because of more energy expended moving the oil when cold. With a block heater, I'd think a car might get better fuel economy than an equivalent 5W-30.
You would still be wasting more energy keeping the oil warm when not in use than you would gain in mileage but I'm sure it's good for the motor. The VI improvers are not as prevalent in synths since they have a large natural viscosity index without improvers. 10w30s need virtually none and a 0w30 doesn't need that much if it starts as a thin 30w. The improvers work well and pretty linearly but wear out over time. It still won't make the same brand of a used synth 10w30 thinner than a 0w30 at cold temps unless they are at different ends of the 30w scale. How a possible answer to the question of 0Ws being bad got to 'it might be to thick' at colder temps is beyond me.
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