5W-20 in 5W-30 applications

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There are very opinionated posters in the 5W-20 discussions here. There seems to be a consensus that there are a couple of things about this oil and the engines that are supposed to use it. 1) It appears the engines are no different than the engines that were specced for 5W-30 oils the model years before, and that the same engines that call for 5W-20 in the U.S. call for higher visc oils in other countries (and in higher performance models using the same engines) 2) No incidences of higher wear or failures have been attributed to the use of 5W-20, and it appears to give as good of service as higher viscosity oils. 3) There may be a mild fuel savings using 5W-20 oils, without any apparent negative results. 4)Many 5W-30 oils shear down to near 5W-20 fairly quickly, so the advantages of using it decrease. So why not use 5W-20 oils in 5W-30 applications?
 
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Even shear-prone 5W-30s don't shear immediately, they are usually thin 30-weights or thick 20-weights at the end of the OCI. So you've still had a 30-weight oil over the majority of the oil change interval. We don't know higher wear is occuring, but there has been some indication from OEM employees that there may indeed be higher wear with 20-wt oils in durability testing (extreme conditions), but it's wear that was deemed acceptable. It depends on the application. Most typical (low horsepower) daily drivers that spend their time loping along the interstate won't even stress a 20-weight. 20-weight is just fine for most cars, but not everybody drives most cars.
 
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Conventional wisdom says you can go up or down one weight from what is recommended without any problem. That's probably true as long as your vehicle is out of warranty. Otherwise there is some risk of waranty coverage denial if there is some (and probably unrelated to oil) failure during the warranty period. My 2 cents.
 
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Here we go again. Boils down to just use what you think is right for your car. Either way you probably wont be wrong. Some 5w20's are almost the same thickness as some 5w30's so just look up the data sheets and pick the one you want to use.
 
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 Originally Posted By: Ben99GT
Even shear-prone 5W-30s don't shear immediately, they are usually thin 30-weights or thick 20-weights at the end of the OCI. So you've still had a 30-weight oil over the majority of the oil change interval. We don't know higher wear is occuring, but there has been some indication from OEM employees that there may indeed be higher wear with 20-wt oils in durability testing (extreme conditions), but it's wear that was deemed acceptable. It depends on the application. Most typical (low horsepower) daily drivers that spend their time loping along the interstate won't even stress a 20-weight. 20-weight is just fine for most cars, but not everybody drives most cars.
I would guess that there is more wear in 20 wt simply for the fact that no onw specs a 5w20 in all of these wear war battles. The one that PP claimes to be the lowest level of wear is a 50wt!
 
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I went from factory spec 5W-20 for nearly 75k miles to 5W-30, simply because I know that Ford made the change for CAFE regulations. I'd rather have some more protection in the long run, even if its negligible. I still get good gas mileage, too.
 
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Honda was likely looking to lower their CAFE numbers, even if they weren't in any danger of being fined. Having the highest "average fuel economy" looks good in ads.
 
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Ledslinger: WRT yr #2, I and others have responded to yr statement many times. Research it yourself. Google is your friend. MarkC: WRT CAFE, you need to read the legislation. Not someone's assertion of what it says, but rather what the law actually provides. Readers' Digest version: CAFE not only penalizes manufacturers whose fleet averages fail to meet the minimum requirements of the law, it provides TEN OF MILLIONS of dollars in incentives to auto manufacturers whose fleet averages exceed the minimum requirements of the law.
 
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 Originally Posted By: MarkC
And having a lot of customers complaining about their engines wearing out wouldn't .
They don't recommend 5W-20 in their higher performance engines.
 

ledslinger

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Ledslinger: WRT yr #2, I and others have responded to yr statement many times. Research it yourself. Google is your friend. You've specifically addressed using 5W-20 in engines where 5W-30 is specified?
 
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 Originally Posted By: Ben99GT
Even shear-prone 5W-30s don't shear immediately, they are usually thin 30-weights or thick 20-weights at the end of the OCI. So you've still had a 30-weight oil over the majority of the oil change interval. We don't know higher wear is occuring, but there has been some indication from OEM employees that there may indeed be higher wear with 20-wt oils in durability testing (extreme conditions), but it's wear that was deemed acceptable. It depends on the application. Most typical (low horsepower) daily drivers that spend their time loping along the interstate won't even stress a 20-weight. 20-weight is just fine for most cars, but not everybody drives most cars.
Couldn't have said it better. Many here are quick to point out how oils and VIIs have improved so much yet they assume all 5w-30s sheer to a 20wt in a few miles. It's just not true.
 
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 Originally Posted By: Ben99GT
 Originally Posted By: MarkC
And having a lot of customers complaining about their engines wearing out wouldn't .
They don't recommend 5W-20 in their higher performance engines.
Examples of which would be?
 
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Where's some evidence (as in facts) that engines using 5W20 wear more than those using 5W30? It may sound as though I'm a 5W20 fan, but I'm not. However, I'd like hard evidence one way or another, rather than guesses and opinions.
 
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 Originally Posted By: MarkC
 Originally Posted By: Ben99GT
 Originally Posted By: MarkC
And having a lot of customers complaining about their engines wearing out wouldn't .
They don't recommend 5W-20 in their higher performance engines.
Examples of which would be?
Honda's S2000, SI Ford's Termi motors, the GT Basically any high output engine is spec'd for a heavier oil. Must be coincidence.
 
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 Originally Posted By: AEHaas
20 grade oils can be used and result in less wear than higher grade oils OEM specified. Here is my latest, search the UOA section for many of my others: http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1543003#Post1543003 Also: These may help you understand viscosity, the first one is more complete: http://ferrarichat.com/forum/faq.php?faq=new_faq_item#faq_haas_articles http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=259902#Post259902 aehaas
You're basing this on UOAs which mean nothing for showing wear. Show me teardowns of an engine run on a 30wt and an engine on 20wt under identical conditions and only then will I start to believe anything.
 
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 Originally Posted By: AEHaas
20 grade oils can be used and result in less wear than higher grade oils OEM specified. Here is my latest, search the UOA section for many of my others: http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1543003#Post1543003
UOAs comparing one viscosity to another prove nothing when that engine hasn't yet broken in. In your case, wear metals would have dropped with any oil. Don't believe me? Run a 60-weight for your next OCI, then we can credit the 60-weight for your lower wear metals. In truth, UOAs aren't the greatest predictors of wear regardless of mileage. This may help you understand UOAs: http://www.bobistheoilguy.com/index.php?...month&Itemid=78
 
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Show me, as in my previous thread, where after almost ten years of use, where 5w20 has been spec'd by Honda and Ford, that there has been increased engine wear, or increased engine failure rate over engines using 5w30. In this thread none could be produced.
 
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