READ PLEASE! 5w20 vs 5w30 engine life? opinions ?

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Correct me if I am wrong - don't most 5w-30's shear down to a 5w-20 in a couple of thousand km'S ? Meaning most cars are running 20 weights for a majority of their OCI's anyway.
 

OVERKILL

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Originally Posted By: nicholas
Correct me if I am wrong - don't most 5w-30's shear down to a 5w-20 in a couple of thousand km'S ? Meaning most cars are running 20 weights for a majority of their OCI's anyway.
No. But many of them can be fuel diluted down to a heavy 20, which of course means the same happens to a 20, it just gets thinner.
 
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Originally Posted By: nicholas
Correct me if I am wrong - don't most 5w-30's shear down to a 5w-20 in a couple of thousand km'S ? Meaning most cars are running 20 weights for a majority of their OCI's anyway.
Maybe 20-25 years ago, ancient history...
 
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It's a fallacious argument, that at it's core makes the assumption that the same things (shear and dilution) don't happen to the 20s.
 

CT8

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Originally Posted By: sayjac
I smell a present or future SynLube SynLube-4-Lifer. 30% shorter engine life eh? As said, this topic hasn't been covered here before. horse Otoh, by the time the thickster tin foil hat crew are done here, you may be their latest champion.
How many people keep their cars enough to wear out their engines?
 
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Originally Posted By: BlueOvalFitter
Originally Posted By: laserred96gt
I think we need a 0w20 vs 5w20 thread now. grin
Hear, hear, I concur! fence
I am on a Grp IV Val 5w-30 syn fill and using 10-30 PYB to top off and my car is loving it. so muted now during idle and cannot discern if the car is actually even on or what not. Still enamored with the 0w-30 and 0w-20s but I keenly want to try to get atleast 1qt of PYB in whatever I use because the car responds with quietness. It's the moly as a FM in the mix! It certainly doesn't hurt that the original fill val 5w-30 has sodium and no moly while the PYB is just the opposite. Opposites attract, who knew!
 
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Originally Posted By: Shannow
It's a fallacious argument, that at it's core makes the assumption that the same things (shear and dilution) don't happen to the 20s.
Right on - pick the oil you want to end up with, not the starting point ... It's the wear at the end of the OIC that counts. New oil is not the issue ...
 
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Originally Posted By: Shannow
It's a fallacious argument, that at it's core makes the assumption that the same things (shear and dilution) don't happen to the 20s.
Well said! That's another myth that's hard to kill. Happy Birthday!
 
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Originally Posted By: BrocLuno
Originally Posted By: Shannow
It's a fallacious argument, that at it's core makes the assumption that the same things (shear and dilution) don't happen to the 20s.
Right on - pick the oil you want to end up with, not the starting point ... It's the wear at the end of the OIC that counts. New oil is not the issue ...
I've been so enamored with PYB 10-30 that I hafta get some in at the onset of an OCI!!
 
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I have a ford wheelchair van that is only driven once a week or less, then a about once a month 800 mile trip to see my daughter and take her out of her group home to see the world. Ford pushrod 3.9L I use 5W30 in it, as it has always had piston slap in the winter is is quieter with the 5W30. Since I use 5W30 in everything else, only one oil needs stocked. If it was not for that I would use 5W20. When make the trip to Iowa, if the windows are clear I drive from motel to highway, 5 minutes/ 1/2 mile , then accelerate gently up to 70 and set the cruise. If possible I leave the heater off until engine is fully warm, when it is very cold, this may take 5 to 7 miles. The van is very slow to warm up, and the thermostat is good.

is there any reason to go back to 5W20 or 0W20

Rod
 
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The Kia my niece owned crapped out at 200k with Pennzoil 5w20 every 10+ conventional not from engine but from constantly going in ditches.
All others family owned was 5w30 and used oil as well as leaked. After 100k.
I should be careful as I am running 0w20 in my Caravan in Louisiana. Ran 5w30, 5w20 and now 0w20
Sister's Altima ran 0w20 for 100k then a mechanic convinced her she caused damage and needed 5w30.
 
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Originally Posted By: bubbajoe_2112
Originally Posted By: Danh
We have a real-world, large number comparison of 5w/20 vs 5w/30 longevity going on right now: Ford vs GM. Ford has recommended 5w/20 for at least a decade while GM continues with 5w/30. If 5w/20 really shortened engine life by 30%, don't you think Ford would be suffering in comparison to GM? It seems to me there is no real perceived difference in engine longevity between the two. The bottom line seems to be that 5w/20 allows an engine to last every bit as long as 5w/30 if the engine was designed with it in mind. Also, let's not forget that a disproportinate amount of wear occurs on cold start-ups, where a lighter grade of oil is helpful. But as others have said, if you feel beter going "thicker", have at it.
Yep, and don't forget that Honda has been running 0W20 in Japan since 2001 with no issues...
If you have statistics that prove it please provide. The only thing I've seen from Japan is a massive amount of imported late model rebuilt engines for sale on eBay. Thousands of them.
There is the government to thank for that.
 
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What if owner's manual states : 5W20 , 5W30 or 10W30 may all be used (with choice dependent on ambient temps expected during oil service life) ... Which do you choose ?
 
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