5W-30 VS.10W-30

Bob

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12
WHAT ARE THE MEASURABLE DIFFERENCES BETWEEN 5/10W-30? HAVE A NEW 2.2L VORTEC ENGINE AND THE MANUAL CALLS FOR 5W BUT 10W IS ACCEPTABLE ABOVE O F. IT IS HARD TO BELIEVE THAT 10W POUR POINT IS THAT MUCH DIFFERENT THAN 5W. I THOUGHT THAT 10W WAS SUPERIOR BECAUSE IT HAS LESS VI'S?
 

Patman

Staff member
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Oakville, Ontario
My biggest beef with 5w30 is that it appears to thin out quicker than 10w30 does, at least according to the oil analysis results I've seen. And a good 10w30 can flow at extremely low temps anyways. IMO, 5w30 (and 5w20 for that matter) is a fuel economy oil, not an engine longevity oil. I'd like to see an engine running 5w30 hit one million miles (or even half that!) before I'm convinced.
 
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Northern California, USA
I think the thinner the oil, the faster the capillary action, and the faster the oil will run into the tighter spots of the engine like between the piston skirts and cylinder walls. I know when my truck is parked outside and it is below freezing, the engine stops clattering faster with a 5w-30 than with 10w-30. I think the oil that splashes against the cylinder walls spreads out faster if it is thinner.
 
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Mahzurrah!
You'd probably be hard pressed to tell the difference in anything other than winter operation, but 10w30 is going the way of the dinosaurs, albeit slowly. All 5w30's are not created equal, there are a good number that hold grade well. With all the engines now thriving on 5w20, your certainly not going to negatively affect an engine running 5w30 in it especially if it's spec'd for it.
 
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Chicago Area
Originally Posted By: Loobed
I think the thinner the oil, the faster the capillary action, and the faster the oil will run into the tighter spots of the engine like between the piston skirts and cylinder walls. I know when my truck is parked outside and it is below freezing, the engine stops clattering faster with a 5w-30 than with 10w-30. I think the oil that splashes against the cylinder walls spreads out faster if it is thinner.
There is no capillary action going on inside an automotive engine.
 
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10,146
Location
Burlington, Ontario, Canada
The 10W-30 grade is not superior but inferior to the 5W-30 grade. This is very much apparent with synthetic oils but can also apply to higher quality mineral oils as well. A cheaply formulated 10W-30 may actually be more shear prone than a typical brand name 5W-30 that uses higher quality base oils and VIIs. The main practical advantage of the 5W-30 grade is that it has a significantly higher viscosity index, so it will be lighter at all start-up temp's. The 10W-30 is largely a legacy grade now as virtually no OEM's specify it any longer.
 
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SE Pa
Originally Posted By: CATERHAM
The 10W-30 grade is not superior but inferior to the 5W-30 grade.
Without further qualification, making such a blanket declaration is wrong. Go talk to Dave at Redline. He will disagree with you as well. Their 10w-30 has less VII and is a more robust oil than their 5w-30. The former is what he specifically recommends in the most severe service where a 30 wt oil is specified.
 
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wisconsin
I have a 2005 Altima 3.5 the owners manual recommends 5w30. But when I look at the Mobil and Pennzoil oil selector they recommend 10w30 for my car.
 
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Originally Posted By: mechtech2
There is no capillary action going on inside an automotive engine.
How are piston pins lubed? not all pistons have holes from the oil control ring to the pin boss. SB Chevy engines didn't have lube holes.
 
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10,146
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Burlington, Ontario, Canada
Originally Posted By: Volvohead
Originally Posted By: CATERHAM
The 10W-30 grade is not superior but inferior to the 5W-30 grade.
Without further qualification, making such a blanket declaration is wrong. Go talk to Dave at Redline. He will disagree with you as well. Their 10w-30 has less VII and is a more robust oil than their 5w-30. The former is what he specifically recommends in the most severe service where a 30 wt oil is specified.
I see you love to quote out of context as I did elaborate. And regarding Red Line, you're wrong. Their 10W-30 is virtually obsolete as their 5W-30 grade contains NO VII's and has the same 3.8cP HTHSV as the 10W-30 grade. I've used both RL grades and would never recommend the low 142 VI 10W-30 oil. In fact their more modern high Vi 0W-30/40 oils I would recommend over RL 5W-30.
 
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Originally Posted By: CATERHAM
A cheaply formulated 10W-30 may actually be more shear prone than a typical brand name 5W-30 that uses higher quality base oils and VIIs.
I wouldn't say that. I see brand name 5W30 shearing to 20 weight all the time in the UOA section and don't remember seeing that with 10W30. I certainly didn't see it myself when I did UOA on QS 10W30 (11 cSt @100C in 4000 miles).
 
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SE Pa
Originally Posted By: CATERHAM
The 10W-30 grade is not superior but inferior to the 5W-30 grade. This is very much apparent with synthetic oils but can also apply to higher quality mineral oils as well. A cheaply formulated 10W-30 may actually be more shear prone than a typical brand name 5W-30 that uses higher quality base oils and VIIs. The main practical advantage of the 5W-30 grade is that it has a significantly higher viscosity index, so it will be lighter at all start-up temp's. The 10W-30 is largely a legacy grade now as virtually no OEM's specify it any longer.
Ok. You elaborated. You're still mistaken. I'll stick with Dave's recommendation for his products.
 
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Burlington, Ontario, Canada
Originally Posted By: friendly_jacek
Originally Posted By: CATERHAM
A cheaply formulated 10W-30 may actually be more shear prone than a typical brand name 5W-30 that uses higher quality base oils and VIIs.
I wouldn't say that. I see brand name 5W30 shearing to 20 weight all the time in the UOA section and don't remember seeing that with 10W30. I certainly didn't see it myself when I did UOA on QS 10W30 (11 cSt @100C in 4000 miles).
But my point is, there is no shortage of 10W-30 dino's that exhibit some oil shear and some high quality 5W-30 and even 0W-30's that don't shear at all. But the real message is that one doesn't have to settle for a low VI 10W-XX oil as today's crop of 5W-30 oils have very acceptable shear rates. If you want a heavier 30wt oil choose a higher HTHSV 5W-30 oil. Reverting to a 10W-30 grade is very much old school thinking.
 
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Lake Forest, CA
Originally Posted By: CATERHAM
But my point is, there is no shortage of 10W-30 dino's that exhibit some oil shear and some high quality 5W-30 and even 0W-30's that don't shear at all. But the real message is that one doesn't have to settle for a low VI 10W-XX oil as today's crop of 5W-30 oils have very acceptable shear rates. If you want a heavier 30wt oil choose a higher HTHSV 5W-30 oil. Reverting to a 10W-30 grade is very much old school thinking.
I believe dino 5W30 today is better than 10 or so years ago, also it is better than today 10W30 in most engines. But the problem I'm facing is my S2000 spec'd only 10W30 for warmer climate (and 5W40 for colder area), since the car is rev'ed to 7-8k daily(after 10-15 minutes drive) and fairly high RPM on highway (4k-5k), I'm reluctant to use dino 5W30. But, if I use syn oil in it then I may mix 3 quarts M1 AFE 0W20 with 2 quarts 0W40 to get a thin 0W30.
 
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Location
Alexandria, VA
Originally Posted By: CATERHAM
Originally Posted By: friendly_jacek
Originally Posted By: CATERHAM
A cheaply formulated 10W-30 may actually be more shear prone than a typical brand name 5W-30 that uses higher quality base oils and VIIs.
I wouldn't say that. I see brand name 5W30 shearing to 20 weight all the time in the UOA section and don't remember seeing that with 10W30. I certainly didn't see it myself when I did UOA on QS 10W30 (11 cSt @100C in 4000 miles).
But my point is, there is no shortage of 10W-30 dino's that exhibit some oil shear and some high quality 5W-30 and even 0W-30's that don't shear at all. But the real message is that one doesn't have to settle for a low VI 10W-XX oil as today's crop of 5W-30 oils have very acceptable shear rates. If you want a heavier 30wt oil choose a higher HTHSV 5W-30 oil. Reverting to a 10W-30 grade is very much old school thinking.
Can you please elaborate.... so you are saying that with today's modern oil, you can no longer generally assume that just because an oil has wider viscosity grade, that it will by default have more polymers that can breakdown and sludge toward the end of it's service life? 2nd question, you are saying that in general with today's synthetics you would chose a wider viscosity range, or just with RL
 
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