Anyone else have mindset of thinner is better?

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As someone who grew up when most manufactures "recommended" only a 5W30 or 10W30 at most (during summer), i was talking to a 74 year old guy the other day that runs 20W50 in his jeep straight 6, i almost dropped to the floor. I could NEVER imagine running something that thick. It seems so out of place in today's engines, unless you have a built turbo, or a Diesel, i cant see any reason to run a motor oil like a 20W50. I kinda even think 5W30 is "old" school with oils like Toyota 0W16 on the market.

I'm even having a hard time using 5W30 in the Elantra, because Hyundai "recommend" a 5W20. (with 5W30 and 10W30 options under certain severe conditions..) I believe the thinner oil has better heat transfer, and flows quicker to the top of the motor on start ups.

I've never seen a engine blow because of thin oil, even on the high revving 3.5L Honda V6 thats in the family, its seen nothing but M1 5W20, and it is smooth as silk even with 214K miles on it.

I also believe a thicker oil is a band aid for loose engine clearances, or a neglected high mileage motor, and is not needed if it has been taken care of.


What are your thoughts on this? am i wrong in my thought process lol?

Thanks!.
 
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I'm even having a hard time using 5W30 in the Elantra, because Hyundai "recommend" a 5W20. (with 5W30 and 10W30 options under certain severe conditions..) I believe the thinner oil has better heat transfer, and flows quicker to the top of the motor on start ups.

I've never seen a engine blow because of thin oil, even on the high revving 3.5L Honda V6 thats in the family, its seen nothing but M1 5W20, and it is smooth as silk even with 214K miles on it.

I also believe a thicker oil is a band aid for loose engine clearances, or a neglected high mileage motor, and is not needed if it has been taken care of.
"Flow" is irrelevant, as long as the oil can be pumped it will flow. And the heat transfer thing is another common red herring as has been shown on here several times.

What you get from a thicker oil is a higher HT/HS which gives a higher MOFT, this is what keeps parts separated and prevents wear. Thinner oils are designed to provide an acceptable HT/HS and acceptable wear, not superior nor better as your title implies.

And yes this topic has been beat to death over the many years here on Bitog.
 

09 GLS

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No, I don't believe that thinner is better. I have heard of many Hyundai dealers using 5w-30 for many cars. We all know why manufacturers move to a thinner oil.

"Flow" is irrelevant, as long as the oil can be pumped it will flow. And the heat transfer thing is another common red herring as has been shown on here several times.

What you get from a thicker oil is a higher HT/HS which gives a higher MOFT, this is what keeps parts separated and prevents wear. Thinner oils are designed to provide an acceptable HT/HS and acceptable wear, not superior nor better as your title implies.

And yes this topic has been beat to death over the many years here on Bitog.
Sorry was not my intention of thick vs thin, but a honest question regarding today's engines and today's superior motor oils.
 
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It's neither better nor worse, just what's right for the engine and how it's used. I tend to like thinner oils if the application allows it.

In racing circles, there's a lot of people that use 15W-40 or 20w-50 oil in a naturally aspirated drag engine that sees <2 minutes total run time with the oil never getting >160*F. A 30 grade is "like water" to these people. They get a bewildered look when I say I'm using a 20 grade and lower.
 
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I ran 20w 50 gtx in my 1984 Toyota 22r engine years ago with no problems. 100 hp pushing 35 inch tires. Looking back maybe 10w 40 would have gained me a 🐎 or 2.
Today I run 5w 30 in my 5.3, but that is the recommended weight.
 
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I run the viscosity for how I will be running the engine and the season. Guess I am still "old school" but 0/20 does not maintain the same running performance during 100-114F summer days as 10w40. And the other way around during winter temperatures.
 
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I fill with what the manual or filler cap has printed on it. If it’s a beater I would step up a grade if necessary but that’s about it.
 

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It's neither better nor worse, just what's right for the engine and how it's used. I tend to like thinner oils if the application allows it.

In racing circles, there's a lot of people that use 15W-40 or 20w-50 oil in a naturally aspirated drag engine that sees <2 minutes total run time with the oil never getting >160*F. A 30 grade is "like water" to these people. They get a bewildered look when I say I'm using a 20 grade and lower.

This. It's about application and the most appropriate choice for the application based on the prevailing operating conditions as well as equipment design. GM's historic spec'ing of 5w-30 for DD duty and 15w-50 for track duty in the Corvette and Camaro. Ford's spec'ing of 5w-20 for the plane-Jane Mustang GT and the spec'ing of 5w-50 for the same car optioned with the "Track Pack" which severely modified or eliminated the thermal castration mechanism is another.

Oil temperature is the key driver in the ability for a given viscosity to be the appropriate choice. This is why we are seeing coolant/oil heat exchangers on more and more vehicles. Controlling operating viscosity by controlling oil temperature allows for the use of a thinner lubricant broadly, with lower risk of wiping a rod bearing via insufficient HTHS visc.

Even then, in severe service or track applications, you will still often see a heavier visc spec'd. That's why the 6.4L and 6.2L HEMI engines spec 0w-40 vs the 5w-20 spec'd for the 5.7L.
 
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