Does 5w30 really offer better engine life?

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Originally Posted By: PT1
According to my GM & Ford engine design friends 10w30 is better.
Well there you have it, straight from the engine designers mouths. Further discussion is pointless. 10w30 is the king of motor oils.
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Originally Posted By: PT1
MPG difference in my Yukon 6.0L is about 2.3 MPG better with the 5w30 so the 10w30 ...
Chances are you are soft pedaling it with the 5w30 so as not to destroy the engine, whereas with the 10w30 you can confidently redline the thing all day long. That is the likely cause of the mpg difference IMHO.
 
ok, did a little research. did a search on 10w30, 5w30 and 0w30 on the OA section, and took some sample numbers. the results i offer for your edification.

10w30
sample size 7
avg vis at 100 11.1
avg Fe/1000 miles 2.22
avg Pb/1000 miles 1.523

5w30
sample size 8
avg vis at 100 9.63
avg Fe/1000 miles 3.57
avg Pb/1000 miles 0.342

0w30
sample size 7
avg vis at 100 10.966
avg Fe/1000 miles 2.07
avg Pb/1000 miles 0.987

only one oil (Schaffer's 5w30) went out of spec, and that only slightly. from this, i would say 0w-30 is the way to go.

sorry to throw some numbers into the discussion, but i thought someone was going to break into singing "Feelings".

tossed a couple out for low mileage, mi vs km, but besides that, i didn't cherry pick or choose oil. this is a mix of cars, oils and mileage...
 
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From a Renewable Lubricants/Chevron Phillips Chemical presentation given at STLE in May titled "High Performance Engine Oils with Vegetable Oil and PAO Blends", Ken Hope, Bill Garmier, slide 15
Quote:
Energy Efficiency
High viscosity index is key to improved wear, reduced fuel dilution and should provide improved energy efficiency.

The high VI formulations provide less lubrication friction in the startup and provide reserved fluid film at higher temperatures.



Maybe VI is a better predictor than just viscosity range increase?
 
Originally Posted By: Drew99GT
What are you tryin to do Patman, start a war?
LOL.gif



Look at the original post date for this topic, it was 6 years ago!

My thoughts have certainly changed since then!!!

For one, I believe 10w30 is an obsolete viscosity, we don't need it when 5w30 will do everything it does, but with the added benefit of flowing better on startup.
 
Originally Posted By: mitchcoyote
The #1 selling grade in the U.S. is 10w-30


That doesn't make it the best choice though, it just goes to show that it's very hard to change people's old habits.

10w30 was a popular recommended viscosity for so long that people just don't want to let go. A lot of people who bought new cars that clearly specify 5w20 in the owner's manual are still buying 10w30, as they think they know better than the engineers that make the cars. The sad thing is, some dealerships think the same way too, and use nothing but bulk 10w30 in all cars, even the ones calling for 5w20.

It's just like the 3000 mile oil change, it's been drilled into us for so long that people still cling to the belief that their engine will die if they don't keep changing the oil every 3k.
 
will do the 5w20 tomorrow, i did this without thinking about it much first and put ALL the bloody metals in the spreadsheet. for 5w20 it will just be vis/fe/pb and mileage.

i suspect that 5w-20 will do just fine, if there is enough data i will do the 0w-20 too, that's what i am planning on running in the miata next OC (down from 0w-40).

patman, didn't notice i had been suckered into responding to an oldie. still, i think that the exercise is worth it.
 
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Mobil 1 5w30 shears down to a 5w20 pretty much all the time, even before 3,000 miles sometimes. Most people who use 5w30 are basically driving with a 5w20 after a few thousand miles.
 
Used to be a 20w-50 fan myself. Then I made the jump to 10W-30 because you know, 5w-30 is just water. Now all I run is 5w-30 and 5w-20 and my 240,000 mile 3.0 Nissan runs smoother than ever. Plus I've picked up 6 mpg. Used to average 18 +/-, now average 24 +/- with the occasional 26. And this is in a 4x4.
 
Originally Posted By: Patman
Originally Posted By: Drew99GT
What are you tryin to do Patman, start a war?
LOL.gif



Look at the original post date for this topic, it was 6 years ago!

My thoughts have certainly changed since then!!!

For one, I believe 10w30 is an obsolete viscosity, we don't need it when 5w30 will do everything it does, but with the added benefit of flowing better on startup.



That's what I said to the guys in Detroit but they said fluid film thickness at start up is more important unless your vehicle sits for days at a time. They also said 10w is better due to less VII's and that some of the 10w synthetics were as good at start up flow as the 5w oils.
 
If I want the flow of a 5w,then I'll just run a 5w. If I want superior flow at any W,then I'll just run a synthetic. Thicker oil creates more friction and therefore more heat and less mpg than thinner oil.
 
ok, here are the other numbers, all listed for one stop shopping...

10w30
sample size 7
avg vis at 100 11.1
avg Fe/1000 miles 2.22
avg Pb/1000 miles 1.523

5w30
sample size 8
avg vis at 100 9.63
avg Fe/1000 miles 3.57
avg Pb/1000 miles 0.342

0w30
sample size 7
avg vis at 100 10.966
avg Fe/1000 miles 2.07
avg Pb/1000 miles 0.987

0w40
sample size 6
avg vis at 100 11.98
avg Fe/1000 miles 1.83
avg Pb/1000 miles 0.29

5w20
sample size 7
avg vis at 100 7.91
avg Fe/1000 miles 1.56
avg Pb/1000 miles 0.13

0w20
sample size 7
avg vis at 100 8.58
avg Fe/1000 miles 1.257
avg Pb/1000 miles 0.62

couple of comments.
this is in one sense a really rough cut. it makes no distinction between oils, applications, etc. on the other hand, this is probably the best way to do a "general" study of oil vis. i think the 0w-20 Pb numbers are a little skewed due to the large number of prius reports (start/stop cycle at every light).

still going to try a interval of M1 0w-20 in the miata. will post the next 0w-40 OA, and then the -20 after that.
 
I still don't think that 10W-30 is that obsolete or 'useless' of a grade of oil. 10W-30's are cold-pump tested down to -25C, and should start a car comfortably down to that temperature. 'Most' places don't get sustained periods of temperatures below -25C, so in 'most' places, this is still a perfectly good year 'round grade.

As well, as we have said, 10W-30 contain less VII's than 5W-30's, so they shear down less, and since they are a bith thicker at startup, they offer a 'bit' more protection and slightly less engine wear.

In cheetahdrivers chart above, ALL those oils, save for 5W-30 and 10W-30, are full syns, or syn blends, so it is not fair to compare wear rates outside of comparing 5W-30 ansd 10W-30, and in that comparo, 10W-30 wins, hands down.
 
I didn't say it was. Just that you should get better mileage with a 5w 20. You can get thin 5w 20's or thicker 5w 20's if you prefer. Alternately,go to a synthetic 5w 20 for possibly better protection. You only have to get .25 of a mpg more to pay for the incremental cost of syn vs. dino over say a 5k oci.
 
Originally Posted By: demarpaint
If a thinner oil provides better mileage isn't it reducing friction which would be causing engine wear?


That's a dang good question! I hope one of our experts will come along and answer it.
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