I am just so amazed that there are folks here with so many posts, but they seem to lack the comprehension of some basic arguments as well as ignore the evidence around them from respected manufacturers.
There is nobody on the so called "thinner is better" oil side, that is saying always use thin oil.
I for one noticed Caterham's signature a long time ago and saw all sorts of viscosities for his different vehicles including 5w50.
They are simply saying the following;
1) All oils are getting technologically better
2) This typically means they are getting more robust
3) This typically means that a 20 weight oil today is better than a 20 weight oil of yesteryear. A 30 weight oil is better than a 30 weight oil of yesteryear. And so on.
4) That in many instances, engines are spending a significant proportion of their time warming up and have oil at a thicker viscosity than ideal
5) That if manufacturers can adequately test improving engines and improving oils together, then by moving to lighter oils, with higher viscosity indexes, oil can be closer to operating viscosity when cold and during warm up and still have adequate viscosity when hot.
What does the evidence show us?
A) Ford developed and tested synthetic blend 5w20 on fully loaded / towing pick up trucks in the desert non stop until 150k. This is way beyond the way that average users will use vehicles spec'd on 5w20.
Since then, the oils have only gotten better.
Are there exceptions? Of course! Surprise surprise, turbos get so hot, they need 30 weight. Turbos have always required a weight or two higher. The fact that turbos can operate on 30 weight just goes to show how much better 30 weight oils are now. If there was no 20 weight oil, no doubt we would have complaints that 30 weight is too light and that 40 should be normal.
Diesels. Diesels can be heavy on oil compared to gasoline engines. That's a design characteristic of the diesel, not a design flaw with 20 weight. Nobody is saying that a 20 weight is as strong as a 30 weight. They are just saying that for a gasoline, non turbo application, a 20 weight is strong enough.
Read this article to learn how much pressure a diesel can put on oil and then talk about it being a failure of 20 weight oil.
Powerstroke Diesel & Oil Change Intervals
B) Toyota & Honda have gone to 0w20 and have back spec'd them for many vehicles.
The Toyota back spec is confusing but one needs to ask why it's confusing. Is it a conspiracy?
Of course not! It's a careful theoretical and field based assessment of whether an engine is suitable for a lighter oil. Perhaps based on design factors or perhaps based on wear so far, or perhaps a combination of the two. It may even be that one of the factors is that older engines have suffered wear from start up (maybe even from 5w30) and they are now unlikely to be suitable for thinner oil due to potential oil pressure drops. That is the general pattern - older engines stay with 5w30, then some can also take 5w20, and then some can also take 0w20. Then into the more recent years, 5w30 is not recommended at all, and in some cases not even 5w20. There are some exceptions, which further suggests there is some very careful design considerations taking place.
In any case, there is an incredible reputation that Toyota need to uphold. There's nothing showing me that they are taking any chances here.
Lastly, those talking about thinner oils are just exploiting the fact that all oils are getting better, so thinner oils can now do a job that heavier oils once did. They are exploiting the fact that folks come here looking for oil recommendations and have engines that are back spec'd and / or are used mostly when cold.
I for one am grateful to have learnt that HTHSV is the correct measure of viscosity and the importance of higher VIs.
I have an OBDII scanner arriving soon so am keen to see what my oil pressure and other indicators are all doing.
There is nobody on the so called "thinner is better" oil side, that is saying always use thin oil.
I for one noticed Caterham's signature a long time ago and saw all sorts of viscosities for his different vehicles including 5w50.
They are simply saying the following;
1) All oils are getting technologically better
2) This typically means they are getting more robust
3) This typically means that a 20 weight oil today is better than a 20 weight oil of yesteryear. A 30 weight oil is better than a 30 weight oil of yesteryear. And so on.
4) That in many instances, engines are spending a significant proportion of their time warming up and have oil at a thicker viscosity than ideal
5) That if manufacturers can adequately test improving engines and improving oils together, then by moving to lighter oils, with higher viscosity indexes, oil can be closer to operating viscosity when cold and during warm up and still have adequate viscosity when hot.
What does the evidence show us?
A) Ford developed and tested synthetic blend 5w20 on fully loaded / towing pick up trucks in the desert non stop until 150k. This is way beyond the way that average users will use vehicles spec'd on 5w20.
Since then, the oils have only gotten better.
Are there exceptions? Of course! Surprise surprise, turbos get so hot, they need 30 weight. Turbos have always required a weight or two higher. The fact that turbos can operate on 30 weight just goes to show how much better 30 weight oils are now. If there was no 20 weight oil, no doubt we would have complaints that 30 weight is too light and that 40 should be normal.
Diesels. Diesels can be heavy on oil compared to gasoline engines. That's a design characteristic of the diesel, not a design flaw with 20 weight. Nobody is saying that a 20 weight is as strong as a 30 weight. They are just saying that for a gasoline, non turbo application, a 20 weight is strong enough.
Read this article to learn how much pressure a diesel can put on oil and then talk about it being a failure of 20 weight oil.
Powerstroke Diesel & Oil Change Intervals
B) Toyota & Honda have gone to 0w20 and have back spec'd them for many vehicles.
The Toyota back spec is confusing but one needs to ask why it's confusing. Is it a conspiracy?
Of course not! It's a careful theoretical and field based assessment of whether an engine is suitable for a lighter oil. Perhaps based on design factors or perhaps based on wear so far, or perhaps a combination of the two. It may even be that one of the factors is that older engines have suffered wear from start up (maybe even from 5w30) and they are now unlikely to be suitable for thinner oil due to potential oil pressure drops. That is the general pattern - older engines stay with 5w30, then some can also take 5w20, and then some can also take 0w20. Then into the more recent years, 5w30 is not recommended at all, and in some cases not even 5w20. There are some exceptions, which further suggests there is some very careful design considerations taking place.
In any case, there is an incredible reputation that Toyota need to uphold. There's nothing showing me that they are taking any chances here.
Lastly, those talking about thinner oils are just exploiting the fact that all oils are getting better, so thinner oils can now do a job that heavier oils once did. They are exploiting the fact that folks come here looking for oil recommendations and have engines that are back spec'd and / or are used mostly when cold.
I for one am grateful to have learnt that HTHSV is the correct measure of viscosity and the importance of higher VIs.
I have an OBDII scanner arriving soon so am keen to see what my oil pressure and other indicators are all doing.
