Which wears less at startup: 5w20 or 5w30?

[rjacket]

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

 

[5sfe91]

I think they are both about the same at start up.

 

[Merkava_4]

5W-20 will get to your bearings 2/100ths of a second faster.

 

[Pablo]

Less wear? Highly theoretical question, actually. Let's stick, for now, with just which one flows better when cold, but you didn't even say cold. Start-up, when? Where? What temp? It really depends on which 5W-20 or 5W-30 you are talking about. Some 5W-20's are very close to 5W-30's, and some 5W-30's are nearly 5W-20's. As for wear, some contend the thinner the better. I agree to some extent. Sure at -60° you want oil pumping and flowing and moving.....but how often will those starts be, vs. 40°F or 20°F? And how much difference will a super thin oil make then? According to some, zero. In most of California - there will be zero provable difference in "wear". So all in all, I think your question is an unintentional, the usual "thick vs. thin" discussion.

 

[tommygunn]

I switched from 5W-30 to 5W-20 in my Honda that recommends 5W-20 and have noticed it takes a lot longer to warm up when it is cold. I am assuming there is less friction with the 5W-20 creating less heat.

 

[rjacket]

Originally Posted By: Pablo

Less wear? Highly theoretical question, actually. Let's stick, for now, with just which one flows better when cold, but you didn't even say cold. Start-up, when? Where? What temp? It really depends on which 5W-20 or 5W-30 you are talking about. Some 5W-20's are very close to 5W-30's, and some 5W-30's are nearly 5W-20's. As for wear, some contend the thinner the better. I agree to some extent. Sure at -60° you want oil pumping and flowing and moving.....but how often will those starts be, vs. 40°F or 20°F? And how much difference will a super thin oil make then? According to some, zero. In most of California - there will be zero provable difference in "wear". So all in all, I think your question is an unintentional, the usual "thick vs. thin" discussion.

So to answer which 5w20 and which 5w30, let's say exactly the same apart from the 20 vs the 30. If the 5w refers to the cold start performance, then assume it is the same. Thus my question was concentrating on whether the 20 vs 30 has any impact on the 5w. What ambient temperature? Let's say a minimum of 32f.

 

[rjacket]

Originally Posted By: tommygunn

I switched from 5W-30 to 5W-20 in my Honda that recommends 5W-20 and have noticed it takes a lot longer to warm up when it is cold. I am assuming there is less friction with the 5W-20 creating less heat.

This is without the effect of the 5w30 being in there when the ambient temperature was warmer compared to when the 5w20 went in?

 

[Pablo]

Originally Posted By: rjacket

So to answer which 5w20 and which 5w30, let's say exactly the same apart from the 20 vs the 30. If the 5w refers to the cold start performance, then assume it is the same. Thus my question was concentrating on whether the 20 vs 30 has any impact on the 5w. What ambient temperature? Let's say a minimum of 32f.

At 32°F no difference. But it does not compute to say "exactly the same apart from the 20 vs the 30". No oils are exactly the same and just have a different 100°C viscosity.

 

[rjacket]

Originally Posted By: Pablo

Originally Posted By: rjacket

So to answer which 5w20 and which 5w30, let's say exactly the same apart from the 20 vs the 30. If the 5w refers to the cold start performance, then assume it is the same. Thus my question was concentrating on whether the 20 vs 30 has any impact on the 5w. What ambient temperature? Let's say a minimum of 32f.

At 32°F no difference. But it does not compute to say "exactly the same apart from the 20 vs the 30". No oils are exactly the same and just have a different 100°C viscosity.

Ok, I guess I meant in both cases take the mid point of the specification that allows you to call it a 5W and just vary the 20 and 30 parts to the mid point that allows you to call them 5w20 vs 5w30. Ok, so let's say, all things being equal including in the following case the viscosity of the 30 element is the same, say 10 on the dot, which one causes less wear at 32f start up temp: 0w30 5w30 10w30 I presume 0w. But on the other hand, would you say there is no difference at 32f between: 5w20 5w30 5w40 or between 0w20 0w30 0w40 or between 10w20 10w30 10w40

 

[Pablo]

Some will just say "the thinner the better at start up." Or "An oil can never be too thin at start-up". That's about all you will get. No one can answer your question with any data or precision. Most any synthetic 0W or 5W or 10W will flow so well at 32° F, there will be no perceptible difference in wear. Of course the 0W will flow the best and in theory, could prevent wear "better", but again 32°F is child's play cold for synthetic oil.

 

[tommygunn]

Originally Posted By: rjacket

Originally Posted By: tommygunn

I switched from 5W-30 to 5W-20 in my Honda that recommends 5W-20 and have noticed it takes a lot longer to warm up when it is cold. I am assuming there is less friction with the 5W-20 creating less heat.

This is without the effect of the 5w30 being in there when the ambient temperature was warmer compared to when the 5w20 went in?

Last winter I used 5W 30 because my Honda has over 200K and I thought it would be better than using 5W 20 with that many miles. Also last winter I could feel heat coming from the heater by the time I got out of my subdivision which is about 6/10 of a mile. This year I am using 5W 20 and on 32 degree mornings there is no heat when I get out of the subdivision and it is about another 1/2 mile before I feel any heat. Last year I was thinking how awesome the car was giving me good heat in such a short amount of time without warming up the engine, now I am disappointed but I may be protecting my engine better with thinner oil at start up. I did switch from 5W 30 PP to 5W 20 Mobil Super 5000 in the past year.

 

[tudorart]

5W-20 is thinner at any temp than 5W30 which is thinner than 5W-40 0W-20 is... 0W-30 ... 0W-40 Even if the winter number is not a measure of kinematic viscosity at start up it is very well correlated to it within the same SAE grade (ONLY). Therefore: 0W-30 is thinner than 5W-30 which is thinner at start-up than 10W-30 so if flow is you want then get the lowest Kvis ... in your case 5W-20 will provide faster flow but will not make a difference unless we're talking about really cold starts. You can always graph your oils on widman's viscosity graphs.

 

[GMorg]

tudorart may be correct for the average of each grade, but Mobil1 0W40 is thinner than Castrol 0W30 at temperatures below about 70F. All 0W40s are not thinner than all 0W30s, but for the average oil, the trend is similar to tudorart's suggestion.