Engine Oils

[andrei79]

Get this very clear .. Alldoes not

so sir what did you recomend grade of oil that will minimize engine vibration and dessipate heat faster ?

[Pinaki]

so sir what did you recomend grade of oil that will minimize engine vibration and dessipate heat faster ?

The shortest range oil that covers the usual ambient temperatures you expect to encounter . For you , if you are living around metro manila and not in the cooler hills , any oil that matches 20w50 or 15w50 grades . As I told you already, Motul 5100 15w50 semi synthetic works very good for pulsar 135LS here . Give it a try .

..The manufacturer of engines tests various grade of these oils and eventually select a particular grade for his engine.
If a layman selects the same grade like 20w40, which the company specified, without going into material science his engine is 'sufficiently lubricated

I do not know how a manufacturer can possibly select one single oil grade for the correct operation of their engine, under all conditions .
With one single "recommended" oil ,it is unlikely for an engine to operate well(or at all) in the Sahara deserts and the Arctic . Or between Jaipur in summer and Kashmir in winter either . They have to specify a range of oils , suitable for the various conditions . Then they also have to test all grades in that range for suitability too .
Either that , or they should forbid you to operate your vehicle beyond certain environment criteria, and void the warranty if you do so .

...The denser or viscous the oil does not mean better lubricant..
My manufacturer recommends 20w40and 20w50.. But fills 20w40all the time, everytime why? Denser or more viscous flows less.. Will take more time to convey heat to the fins.. He should always fill 20w50as per your logic. I agree if clearances can take any, w50 will protect more as its film would be stronger but we have to consider everything and flowability should be prioritised hence w40 is better and thats what it fills up on priority in my engine...

Again you are using density and viscosity interchangeably . Viscosity is not measured from density , but from flow . SAE grades are about viscosity(flow) . SAE grade of an oil does not specify it's density .

The denser or viscous the oil does not mean better lubricant..

Well, for mineral engine oils, denser oils does mean better lubrication . While lubricity is not related to it's viscosity .

Denser or more viscous flows less.. Will take more time to convey heat to the fins..

Again flow is not directly related to density . Mercury(a dense metal), flows way better than mucho less dense honey or milk .

..You dont add viis to make it flow less!! Better flow better the lubricant(w40 flows better than w50, same logic as above), You add viis so that your better cold lubricant(base oil) dont thin a lot to land up in combustion chamber..

VIIs don't stop an oil from thinning . It prevents an oil from flowing beyond a certain limit, when thinned by heat . i.e it improves Viscosity Index . That is why we call it Viscosity Index Improver . The oil remains thin but is not able to flow away so quickly so as to leave the metal bare . So - make oils flow less is what it exactly does . You are right - w40 flows better than w50 , but that is because it has less VII in it than w50 . Less VII = better flow . More VII = less flow . So you tell me now why we add VIIs in mineral oils .
Again better flow = better lubricant ?? how ?? Water flows way way better than graphite , but graphite is used as lubricant , not water .

[Ri$hi]

Does Motul provides mineral oil in 20w50 grade?

[muztariq]

The shortest range oil that covers the usual ambient temperatures you expect to encounter . For you , if you are living around metro manila and not in the cooler hills , any oil that matches 20w50 or 15w50 grades . As I told you already, Motul 5100 15w50 semi synthetic works very good for pulsar 135LS here . Give it a try .

I do not know how a manufacturer can possibly select one single oil grade for the correct operation of their engine, under all conditions .
With one single "recommended" oil ,it is unlikely for an engine to operate well(or at all) in the Sahara deserts and the Arctic . Or between Jaipur in summer and Kashmir in winter either . They have to specify a range of oils , suitable for the various conditions . Then they also have to test all grades in that range for suitability too .
Either that , or they should forbid you to operate your vehicle beyond certain environment criteria, and void the warranty if you do so .
Again you are using density and viscosity interchangeably . Viscosity is not measured from density , but from flow . SAE grades are about viscosity(flow) . SAE grade of an oil does not specify it's density .
Well, for mineral engine oils, denser oils does mean better lubrication . While lubricity is not related to it's viscosity .


Again flow is not directly related to density . Mercury(a dense metal), flows way better than mucho less dense honey or milk .

VIIs don't stop an oil from thinning . It prevents an oil from flowing beyond a certain limit, when thinned by heat . i.e it improves Viscosity Index . That is why we call it Viscosity Index Improver . The oil remains thin but is not able to flow away so quickly so as to leave the metal bare . So - make oils flow less is what it exactly does . You are right - w40 flows better than w50 , but that is because it has less VII in it than w50 . Less VII = better flow . More VII = less flow . So you tell me now why we add VIIs in mineral oils .
Again better flow = better lubricant ?? how ?? Water flows way way better than graphite , but graphite is used as lubricant , not water .

i agree with most of your points and appreciate the effort you have made to make all understand the concept but there are some things i would like to highlight.
If better flow is not better lubricant.. Then why not use grease in engine.? I meant of all the grades a manufacturer enlists for your kind of envt.. Selecting a lower viscosity oil will provide better lubrication, as it will flow fast during the cold start.. 75 percent of engine wear on commuter vehicles happen during cold starts we are worried too much about the remaining 25 percent.
Regarding you saying how come manufacturer select only one or two grade of sae grades, even i am always worrying how.. Even tho a 20w40 or a 20w50 oils seems to be well between the ambient temp of oir country but some months in kashmir are missed out on that recommendation :-) car manufacturer gives a good range of oils.. My santro has some total 10 recommendations ranging from 5w20 to 20w50!!
Regarding your saying that sae only considers viscosity and not density is also not correct.. They are the pioneers in engine oil standards are very promt in updating the standards as per changing scenario..
The kinematic viscosity is not just measure of viscosity.. Its equal to dynamic viscosity/density.. So density does come into picture.

By using viscous grades we are going back 60-70 years in time when in cold different straight weight oil was used and in summer a different straight oil was used.. The system of multigrade was developed just to ensure cold start protection even in summers! So that one can use a simple multigrade oil all round the year and gets benefitted.
Each test that sae has, has its own history.. Like some 20 30 years ago there was a lot of engine failures during a cold winter even when they were on multigrade oils like 10w40.. Which is sufficient for those temps.. But the problem was that the oil was not being pumped from the sump by the pump.. Hence came the pumping viscosity test..
Just go to sae.org and you will realise what is their expertise.. They have a standard for everything, where even a bit of engineering is involved!! They have developed a system so efficient that everyone around the world is following it.

What we see in that system is just viscosity.. But thats very carefully chosen system!!

Regarding your lubricity and density and viscosity comparison of mineral and synthetic.. One should always be clear that its the viscosity which plays a vital role and not mineral or synthetic nature.. Thats why Motul 15w50 300v is having all kinds of parrafins etc to reach that viscosity.. Just read its msds.. You would be astonished, what all they have added!! To meet 15w50 spec of sae.. If you bring an ester in the engine alone.. It will land up in the combustion chamber soon its so thin(less dense and less viscous). If viscosity does not play a role, how come synthetics are better lubricants.. They are less dense and also less viscous (flows readily).
Also, its not that a material having more flow will run away from metal.. Its the surface tension which decides whether a material will stick to a metal or will move away and not its flowability.
When some manufacturer recommends 10w30, it doesnot only mean that engine clearances are w30 based, but it also means that oil pump, oil filter, bearing clearances etc are all capable of a less dense oil usage.. Any usage of 20w40 or 20w50 in even summers may not be handled by the other components. Hence its always beneficial to go with manufacturer recommendations.. He knows the engine inside out.. Of course the svc will provide you with asistance in case you live in kashmir or jaipur.. In kashmir you may have starting problems, thats it. in jaipur you may lose that grade oil faster.. Both are easily treatable and may never be repeated by the user!

Your saying more vii less flow is also incorrect. A straight weight 30 will have less flow than a 10w30 even tho a 10w30 has good amount of viis and a straight weight has none. Read the example given in the link attached. Also a 5w20will flow faster than 10w40.. Evwn tho both have same vii. Its all in viscosity. There is something called temporary loss of viscosity there.

A great article published by sae some 11years ago.

https://www.sae.org/news/releases/rightoil.htm

[Pinaki]

...If better flow is not better lubricant.. Then why not use grease in engine.?

Then why not use water ? Surely it will have one of the best flow ? Point is .. there are other properties of petroleum based lubricating oils which suits it to the purpose at hand and therefore we have been using it , rather than many other stuff which may excel in one of the necessary properties but fails in others . Depending upon the application .

What do you think they used to lubricate steam railroad engines ? Lard first , then they shifted to advanced tech - grease .

car manufacturer gives a good range of oils.. My santro has some total 10 recommendations ranging from 5w20 to 20w50!!

They are very right , better listen to them .

..Selecting a lower viscosity oil will provide better lubrication, as it will flow fast during the cold start.. 75 percent of engine wear on commuter vehicles happen during cold starts we are worried too much about the remaining 25 percent...

Yes you are correct in that near about 75% of engine wear occurs during startup . This was the theory once .. since then engine manufacturers build lands and grooves inside the engine and bearings in all vital areas , which retains small amount of oil even after the engine is stopped (this oil never drains back to the sump) and prevents the majority of the cold startup wear next morning .
Also it is not like 75% of the wear occurs with 20w40 and that becomes 0% with 10w40 or 5w40 . It reduces by a few percentages only . All engine heads have an oil-circulation inspection screw/nut/view-port . After cold cranking oil would reach the head in less than 5-10 secs (I have checked it by removing this inspection nut). There will be difference between 10w40 and 20w40 in this initial reaching time of 1-2 seconds only . i.e the wear due to cold cranking is reduced by range of 70% from 75% max .... you still have 70% initial wear in your engine due to cold start every morning with your 10w40 oil .
Again I cannot agree that any oil will lube better (i.e cause less friction and wear) because it flows quickly . Motion of oil does not cause lubrication .

...Regarding your saying that sae only considers viscosity and not density is also not correct.. They are the pioneers in engine oil standards are very promt in updating the standards as per changing scenario..
The kinematic viscosity is not just measure of viscosity.. Its equal to dynamic viscosity/density.. So density does come into picture...

"The Society of Automotive Engineers (SAE) has established a numerical code system for grading motor oils according to their viscosity characteristics. SAE viscosity gradings include the following, from low to high viscosity: 0, 5, 10, 15, 20, 25, 30, 40, 50 or 60. The numbers 0, 5, 10, 15 and 25 are suffixed with the letter W, designating their "winter" (not "weight") or cold-start viscosity, at lower temperature. The number 20 comes with or without a W, depending on whether it is being used to denote a cold or hot viscosity grade. The document SAE J300 defines the viscometrics related to these grades.
Kinematic viscosity is graded by measuring the time it takes for a standard amount of oil to flow through a standard orifice, at standard temperatures. The longer it takes, the higher the viscosity and thus higher SAE code." - Unedited quote from Wikipedia .

I do not see the word "density" mentioned anywhere here .

..By using viscous grades we are going back 60-70 years in time when in cold different straight weight oil was used and in summer a different straight oil was used.. The system of multigrade was developed just to ensure cold start protection even in summers! So that one can use a simple multigrade oil all round the year and gets benefitted...

You have to understand that modern multi grade mineral (petroleum refined) oils are the same mono grade oils from 60-70 years ago .. since we have not developed a different pertoleum in all this time . The source and material is the same with same properties, since we dug up our first barrel of petroleum . Modern multigrade oils are those same oil with a little bit of additive in it to make it behave better for our purposes .

...Regarding your lubricity and density and viscosity comparison of mineral and synthetic.. One should always be clear that its the viscosity which plays a vital role and not mineral or synthetic nature.. Thats why Motul 15w50 300v is having all kinds of parrafins etc to reach that viscosity.. Just read its msds.. You would be astonished, what all they have added!! To meet 15w50 spec of sae.. If you bring an ester in the engine alone.. It will land up in the combustion chamber soon its so thin(less dense and less viscous). If viscosity does not play a role, how come synthetics are better lubricants.. They are less dense and also less viscous (flows readily).

I am not discussing synthetic oils here (yet) .

...When some manufacturer recommends 10w30, it doesnot only mean that engine clearances are w30 based, but it also means that oil pump, oil filter, bearing clearances etc are all capable of a less dense oil usage.. Any usage of 20w40 or 20w50 in even summers may not be handled by the other components. Hence its always beneficial to go with manufacturer recommendations.. He knows the engine inside out.. Of course the svc will provide you with asistance in case you live in kashmir or jaipur.. In kashmir you may have starting problems, thats it. in jaipur you may lose that grade oil faster..

Then explain me this . Hero Honda recommended (in writing in their owner's manuals) servo mutligrade 20w40 for all their engines . Then once they started to sell their own 10w30 oil they changed that recommendation(again in writing) to 10w30 only , going so far as to say that they'll void your engine's warranty if you use anything other than HH premium 4T 10w30 . This oil change also applied to the millions of vehicles they had already sold by then , since thier ASCs were instructed to sell, stock, and fill the HH 10w30 only, exclusively . So how come did they changed the oil-pumps , bearing clearances , oil-filter etc etc of the millions of vehicles they had already sold by then ??
Also note that Honda , who supplied almost all of their engines then .. continued to recommend 20w40 for our climates in the Indian plains (until recently).
So although I usually advice people to stick to manufacturer's manuals , I also recommend some common sense with it .

...Your saying more vii less flow is also incorrect. A straight weight 30 will have less flow than a 10w30 even tho a 10w30 has good amount of viis and a straight weight has none. Read the example given in the link attached. There is something called temporary loss of viscosity there.
A great article published by sae some 11years ago.
How Do You Choose the Right Type of Oil for Your Car?

A straight 30 weight oil will have less flow than 10w30 yes , not because it lacks VIIs, but because the 10w30 oil is really a 10 weight oil (with some additives in it). Remember the number before the w denotes the weight of the base oil . SAE 30 weight oil flows less than SAE 10 weight as defined by SAE viscometric grading . So , what's surprising in it ?

The document you refer to , too does not blame VIIs for the temporary loss of viscosity phenomenon . It says that the same occurs in case of extreme restriction of oil path and simultaneous increase in pressure .
And I quote ... "Consider a small pipe through which oil is being pumped at a constant pressure. At a relatively low rate of flow, an SAE 30 or SAE 10W-30 will pass through at the same speed. Now constrict a portion of the pipe to a very small diameter and increase the pressure. Under these conditions, more SAE 10W-30 oil will flow out the end of the pipe in a given time period. Why? In the case of the multigrade oil, there has been a reduction in resistance to flow, a reduction in viscosity in the narrow, constricted portion of the pipe. Since there is less resistance, more SAE 10W-30 can be pumped through. But this is only a temporary loss of viscosity. Remove the constriction and both oils again flow through the pipe at the same speed."

[muztariq]

Then why not use water ? - You are still not getting my point - If manufacturer recommends two grades, one viscous and other less viscous its better to use less viscous. If someone gives me an 2040 rated water.. i will even use that.

Yes you are correct in that near about 75% of engine wear occurs during startup . This was the theory once .. since then engine manufacturers build lands and grooves inside the engine and bearings in all vital areas , which retains small amount of oil even after the engine is stopped (this oil never drains back to the sump) and prevents the majority of the cold startup wear next morning .
Also it is not like 75% of the wear occurs with 20w40 and that becomes 0% with 10w40 or 5w40 . It reduces by a few percentages only . All engine heads have an oil-circulation inspection screw/nut/view-port . After cold cranking oil would reach the head in less than 5-10 secs (I have checked it by removing this inspection nut). There will be difference between 10w40 and 20w40 in this initial reaching time of 1-2 seconds only . i.e the wear due to cold cranking is reduced by range of 70% from 75% max .... you still have 70% initial wear in your engine due to cold start every morning with your 10w40 oil . I never said I will be 100% protected, but using a less viscous oil from the "recommended grades" will make it somewhat better, and if I can further reduce that thing by using 10W40, I can go a little further

You have to understand that modern multi grade mineral (petroleum refined) oils are the same mono grade oils from 60-70 years ago .. since we have not developed a different pertoleum in all this time . The source and material is the same with same properties - Same is with the material of construction of our engines!! We haven't started using titanium while constructing engines!

"The Society of Automotive Engineers (SAE) has established a numerical code system for grading motor oils according to their viscosity characteristics. SAE viscosity gradings include the following, from low to high viscosity: 0, 5, 10, 15, 20, 25, 30, 40, 50 or 60. The numbers 0, 5, 10, 15 and 25 are suffixed with the letter W, designating their "winter" (not "weight") or cold-start viscosity, at lower temperature. The number 20 comes with or without a W, depending on whether it is being used to denote a cold or hot viscosity grade. The document SAE J300 defines the viscometrics related to these grades.
Kinematic viscosity is graded by measuring the time it takes for a standard amount of oil to flow through a standard orifice, at standard temperatures. The longer it takes, the higher the viscosity and thus higher SAE code." - Unedited quote from Wikipedia .

I do not see the word "density" mentioned anywhere here .

You donot see the word density.. The moment I say Kinematic viscosity =(dynamic viscosity divided by density) Density comes into picture! Just attaching an image..Density of water and honey is nearly same.. see the difference in the kinematic viscosity.
That why its better to go by SAE grades.. there are so many experts who are waiting to challenge everything but putting SAE grade oil in their vehicle!! Its an excellent system without doubt.. People were challenging einsten and even proved him wrong but just a month back retracted saying there was a mathematical error in their calculation!! I am not saying dont challenge - Challenge, but be open!


Then explain me this . Hero Honda recommended (in writing in their owner's manuals) servo mutligrade 20w40 for all their engines . Then once they started to sell their own 10w30 oil they changed that recommendation(again in writing) to 10w30 only , going so far as to say that they'll void your engine's warranty if you use anything other than HH premium 4T 10w30 . This oil change also applied to the millions of vehicles they had already sold by then , since thier ASCs were instructed to sell, stock, and fill the HH 10w30 only, exclusively . So how come did they changed the oil-pumps , bearing clearances , oil-filter etc etc of the millions of vehicles they had already sold by then ??
Also note that Honda , who supplied almost all of their engines then .. continued to recommend 20w40 for our climates in the Indian plains (until recently).
So although I usually advice people to stick to manufacturer's manuals , I also recommend some common sense with it .

I dont know why hero honda started using 10w30.. I cant justify that also. But I want to inform you that using a nonrecommemded oil (mainly viscous oils in summer) may have a bigger impact than what meets the eye - a 20W50 may not flow from an oil filter similarly as a 10W30. please note I am not talking HH here - Practically we are doing it without any visible damage.


A straight 30 weight oil will have less flow than 10w30 yes , not because it lacks VIIs, but because the10w30 oil is really a 10 weight oil - No, It behaves like a 10 weight oil when cold, but is actually a 30w oil when hot. At room temperature you will not compare a 10W30 with straight weight 10 but a straight weight 30!!. Remember the number before the w denotes the weight of the base oil . It denotes weight of the base oil at cold temp. a 5W and 20W may have same (similar*) flow at room temp. At room temp its actually the number after W that matters more.. a W40 and W50 no matter how much VIIs they have are different! A 10W40 will flow similary to a 20W40 no matter how much more VIIs 10W40 has (actually 2 times more as per you)

* Similar means there is a very marginal difference - which I utilise by using 10W40 in place of 20W40

and SAE 30 weight oil flows less than SAE 10 weight as defined by SAE viscometric grading . So , what's surprising in it?

Surprising is your comparison of 20W40 with 20W50 based on VIIs. A 20W40 is viscous than 20W50 at room temp. The number before w even if same is nowhere related to viscosity!! And regarding VIIs and flow 20W40 will not flow more because of it has less VIIs but because it is less viscous!!
"

OK Ok.. Now I understand your thinking why you ask people to use 20W40 in winters and 20W50 in summers - You actually think both flow similarly at room temp as number before W is same! How wrong you are! 20W50 is much more viscous at room temp! You are actually jeopardising the initial flow!! Though your logic of w50 in place of w40 holds somewhat good during operation as ambient temp is towards higher side.. but let me tell you in a w40 recommendation w50 shouldn't be used in regular operation.. high speed constant rides calls for a w50 grade; nothing else!! I have never had a loss using w40 grade in summers and even 10W30 grade HHs dont see a leak in summers.

Again you are worrying too much for operational lubricity and jeopardising the cold start!!
Let me also tell you 15W50 will have marginally less flow than 20W40 at room temp. Even though 15W seems lower than 20W but at room temp its actually the value after W that matters more!!

Again I will conclude (for those who want more protection) - 10W40 grade oil is better at any Indian Temp! and can be replaced when manufacturer recommends w40 grade in the manual.. But use it with earlier change intervals than manufacturer recommended interval to account for VII loss.
Question is how much early -
Regular use - extend it till 80% of Manufacturer recommendation. (2400 km in place of 3000 km recommendation)
Severe use - 60% of Manufacturer recommendation. (1800km in place of 3000 km recommendation)
Extremely severe use - Go synthetic!! You may even have to change it every week/300 km based on severity !!

Replies in Color

Again see the attached file: As per you mercury can be used as it flows faster; is Dense, actually quite dense (thick - and thicker is better as per you) - But the poor compound is having no kinematic viscosity. Mercury does not flow faster because it has low viscosity, actually it has higher dynamic viscosity than water, it is also dense, but it flows faster because it has "low kinematic viscosity" as kinematic viscosity is dynamic viscosity devided by density.. Though dynamic Viscosity is high, as it has high density kinematic viscosity is impacted! and that low kinematic viscosity is not allowed by SAE, thats why water cant be used also. But if someone modifies water to meet a 20W40SAE spec I would put it straight in my engine.
Hope you get kinematic viscosity right!



I also know you will prove yourself right even after all this - But I must make an effort!
I dont know it all, but I know as much oil as should be required.. I use 10W40!! Smiling all along!!

[muztariq]

You are again confusing and using the words thin/thick interchangeable with viscosity . Thinning is not the same as reduction in viscosity .

i also hope i have clarified all these points in my above colorful post..

[andrei79]

The shortest range oil that covers the usual ambient temperatures you expect to encounter . For you , if you are living around metro manila and not in the cooler hills , any oil that matches 20w50 or 15w50 grades . As I told you already, Motul 5100 15w50 semi synthetic works very good for pulsar 135LS here . Give it a try .

I do not know how a manufacturer can possibly select one single oil grade for the correct operation of their engine, under all conditions .
With one single "recommended" oil ,it is unlikely for an engine to operate well(or at all) in the Sahara deserts and the Arctic . Or between Jaipur in summer and Kashmir in winter either . They have to specify a range of oils , suitable for the various conditions . Then they also have to test all grades in that range for suitability too .
Either that , or they should forbid you to operate your vehicle beyond certain environment criteria, and void the warranty if you do so .
Again you are using density and viscosity interchangeably . Viscosity is not measured from density , but from flow . SAE grades are about viscosity(flow) . SAE grade of an oil does not specify it's density .
Well, for mineral engine oils, denser oils does mean better lubrication . While lubricity is not related to it's viscosity .


Again flow is not directly related to density . Mercury(a dense metal), flows way better than mucho less dense honey or milk .

VIIs don't stop an oil from thinning . It prevents an oil from flowing beyond a certain limit, when thinned by heat . i.e it improves Viscosity Index . That is why we call it Viscosity Index Improver . The oil remains thin but is not able to flow away so quickly so as to leave the metal bare . So - make oils flow less is what it exactly does . You are right - w40 flows better than w50 , but that is because it has less VII in it than w50 . Less VII = better flow . More VII = less flow . So you tell me now why we add VIIs in mineral oils .
Again better flow = better lubricant ?? how ?? Water flows way way better than graphite , but graphite is used as lubricant , not water .

just a question sir pls enlightened me which of these two (density or vicosity) determines the proper heat dessipation of the engine?
and which is to determine that the oil will travel the tightest part of the engine to dessipate heat and properly lubricated? is it that if higher vicosity will not travel in tiny clearance of the engine or it will still travel but very slow

[amitmalve]

Well, I just went through the discussion between Pinaki sir & Muztariq ji. I appreciate the efforts taken by both of them. It will really help a lot in educating other members including me.

But, I am now a bit confused regarding which oil is best suited for normal Indian riding conditions(not considering extreme cold & hot regions/climatic conditions) amongst 10w40 & 20w40.

Actually I remember one very important point told by Pinaki sir some time back -
'Wide range oils like 5w40, 10w40, 15w50 use lots of the additives needed to obtain such wide range of viscosity . These Vii's themselves have no lubrication properties and degrade easily into sludge inside the engine . Moreover , more Vii additives means less actual oil in it for real lubrication and cooling . Sludge from wide range oils gum up pistons rings and bearings . 10W40 oils require about 3 times the Vi concentration to get the spread between 10 and 40 as a 10W30 oil does .
In the mid eighties Ford stopped listing 10w40 as a recommended oil in their engines. They were having sludge problems in the V8 engines . API now considers the 10w40 etc grades as obsolete . In order for a 10W40 oil to meet the stringent API SL requirements of today the VI package has to be pure synthetic and very very high quality and high performance. As a result, the 10W40 of today is not an issue for deposit formation.'
(but currently we are not talking about fully synthetic oils) (this is the maximum range of climatic conditions one would face under normal riding conditions in India.)

So 10w40 will contain more additives than actual oil compared to 20w40 and it is the actual oil (& not additives) which gives the engine real lubrication & protection.

Am I right?

[muztariq]

Well, I just went through the discussion between Pinaki sir & Muztariq ji. I appreciate the efforts taken by both of them. It will really help a lot in educating other members including me.

But, I am now a bit confused regarding which oil is best suited for normal Indian riding conditions(not considering extreme cold & hot regions/climatic conditions) amongst 10w40 & 20w40.

Actually I remember one very important point told by Pinaki sir some time back -
'Wide range oils like 5w40, 10w40, 15w50 use lots of the additives needed to obtain such wide range of viscosity . These Vii's themselves have no lubrication properties and degrade easily into sludge inside the engine . Moreover , more Vii additives means less actual oil in it for real lubrication and cooling . Sludge from wide range oils gum up pistons rings and bearings . 10W40 oils require about 3 times the Vi concentration to get the spread between 10 and 40 as a 10W30 oil does .
In the mid eighties Ford stopped listing 10w40 as a recommended oil in their engines. They were having sludge problems in the V8 engines . API now considers the 10w40 etc grades as obsolete . In order for a 10W40 oil to meet the stringent API SL requirements of today the VI package has to be pure synthetic and very very high quality and high performance. As a result, the 10W40 of today is not an issue for deposit formation.'
(but currently we are not talking about fully synthetic oils) (this is the maximum range of climatic conditions one would face under normal riding conditions in India.)

So 10w40 will contain more additives than actual oil compared to 20w40 and it is the actual oil (& not additives) which gives the engine real lubrication & protection.

Am I right?

[shoeb2015]

Muztariq and Pinaki ji ,I appreciate the efforts taken by both of you.
It will really help busting myths and doubts related to engine oils.

Why did HH mention the oil drain interval to be 6000 kms in the owner's manual ?

I have seen many people strictly following 6000km oil change period(with top-ups in between) and when the engine oil is drained it looks like if it has been drained from a diesel engine but the engine lasted a good 80k+ kms.

[muztariq]

Muztariq and Pinaki ji ,I appreciate the efforts taken by both of you.
It will really help busting myths and doubts related to engine oils.

Why did HH mention the oil drain interval to be 6000 kms in the owner's manual ?

I have seen many people strictly following 6000km oil change period(with top-ups in between) and when the engine oil is drained it looks like if it has been drained from a diesel engine but the engine lasted a good 80k+ kms.

you will get the answere when you read this- i own a santro and my friend owns a wagon r. My oil change interval is 5000km/six month. My friends 10,000 km or 1year. I used to change oil every 4 months castrol magnatec 5w30 1000 rs for 3l oil. Whereas my friend changes every year! My maintenance costs is 3600/ year his is 1200 per year(including oil filterz).. To set the equation right i put total quartz 5w40 fully synthetic now for 4400/4litre( i keep 1l for next change) and change oil every year/12000 kms.. But still my maintenence costs are higher than him.. Its just pure marketing!
Regarding quality of oil- modern oils are very durable, co es with lot of antioxidants and surfactants. Black oil doesnot mean dead oil.. Yes, if you are going to leave the vehicle for 2-3 months it will form sludge and get deposited, otherwise nothing bad happens on regular usage.
The bad that will happen would be thinning of oil due to vii loss etc and subsequent thinning and burning of oil.. Thats more problematic. The whole oil thins down and starts burning and slight top up doesnot resolve the issue. Also thinning will reduce protection power of oil.. Hence not advisable - if oil was not getting lost till say 4000 kms and then it starts reducing.. The whole oil should be changed.
Also, this figure is unrealistic -may work for low cc engines or fluid cooled engine or synthetic oils.. But a 150cc or above on aircooling and mineral oil.. Oil should be changed around 3000 kms max.

Also, as you have mentioned 80k km.. I have something more for you.

Its not about the engine life in kms.. Its about performance.
An ill maintained engine will give cold start problems.. Engine would be very rough.. Acceleration wouldnt be smooth.. Will stop at any place, will not be reliable and can't be taken out even at 12 in the night.. Will consume a lot of oil..
80k done with these problems are not worth doing.
I met a person like that at my mechanic.. He saw my shell 750rs bottle and started smiling.. When i asked why? His reply was.. Not worth, i have this discover 125, i put diesel engine oil in it and continue for six months.. It costs 180 bucks per fill.. If i use it for 10 years i will consume 3600 and after 10 years i will open up the engine and get it overhauled and consume 3000 bucks.. Much much cheaper than you!! And does this oil state that you will not require an overhaul after 10years?
Actually he was very right.. If the price remains same i would have consumed 15000rs oil.. And who knows if i still require an overhaul.
But i cant take a chance on reliability even for a second, forget about years!!

[Pinaki]

.... At room temperature you will not compare a 10W30 with straight weight 10 but a straight weight 30!! .... 20W50 is much more viscous at room temp! ..... The number before w even if same is nowhere related to viscosity!!

Where did you get all this ? The number before the w denotes the SAE grade of the base oil

i also hope i have clarified all these points in my above colorful post..

Ummm ... Have you ever measured viscosity, density, thermal-conductivity, surface-tension etc etc of stuff in a physics lab ? I mean hands on ? It is very difficult to grasp the physical properties of materials including petroleum fractions like oil etc just by reading MSDS published by people . The data provided is not incorrect , but is subject to judicious interpretation .. before one can put them to work .

just a question sir pls enlightened me which of these two (density or vicosity) determines the proper heat dessipation of the engine?
and which is to determine that the oil will travel the tightest part of the engine to dessipate heat and properly lubricated? is it that if higher vicosity will not travel in tiny clearance of the engine or it will still travel but very slow

Both have been considered by the engine builders under all reasonable operational conditions . No engine maker will be stupid enough to provide oil-paths too narrow for any grade of oil that is commonly used by vehicle owners, . If they make a mistake in that , they'll have erred on the side of caution . i.e made those oil paths wider than required . So don't worry .

...Why did HH mention the oil drain interval to be 6000 kms in the owner's manual ?

I have seen many people strictly following 6000km oil change period(with top-ups in between) and when the engine oil is drained it looks like if it has been drained from a diesel engine but the engine lasted a good 80k+ kms.

That recommendation was made by Honda Japan for standard test conditions . They have tested this particular oil there and certify to this . 6000kms may not be a problem under standard test conditions there - like riding constantly at 40kmph on smooth hole-free roads , with excellent quality fuel , very very clean dust and pollution free environment , cool climate with little temperature variation , disciplined and low traffic etc etc .. that is prevalent in Japan . At least my HeroHonda ASC forbid me to use this oil beyond 3000kms .
Moreover it is not only Honda , but all vehicle makers shifting to lower weight based oils for more kms per liter to conform to pollution norms dictated by CAFE which is becoming compulsory worldwide now . At the cost of engine life of course , now why would they worry about that ?
Also consider that these old honda engines are very forgiving, Discovery Channel ran the honda C90 cub(Splendor/CD/Passion etc have this same engine) on used cooking oil they borrowed from a fast food outlet (after the days fries) . They said that "it actually ran a little better on it " .

[amitmalve]

Well, if this is the case I would also like to use this shell 10w40 ax7. Only 3% additives & 97% actual oil is good enough for me.
Actually I have used this oil (ax7) during winters & was pretty satisfied with its performance. But I was a just bit reluctunt to use it in summer being a 10w40(so currently using motul 20w40).

Do write in your experience with this oil(ax7). I want to know how does it performs in current hot climatic conditions.

[muztariq]

10w30 oil is really a 10 weight oil (with some additives in it). Remember the number before the w denotes the weight of the base oil . SAE 30 weight oil flows less than SAE 10 weight as defined by SAE viscometric grading . So , what's surprising in it ?

The number before the w denotes the SAE grade of the base oil

The first number (the "5" in 5w30) is only a relative number which basically indicates how easily it will allow an engine to "turn over" at low temperatures. It is NOT a viscosity reference. In other words, a 10w30 is NOT a 10 weight oil in cold temperatureswww.hyperformancecycles.net/oil_bible.pdf

I have been diagnosed with 'migraine' and experiencing excruciating pain and cant see monitors/mobile screens etc.. Too much typing from Mobile AMOLED, Computer LCD has done its job.. This is my last post(with permission from doctor) till I get well again!

Cheers