Thicker is better in my opinion.

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467
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NYC
There is a theory which floats around on the internet that thinner oil circulates better around the engine during startup preventing wear but I found this theory.to be false. Ive been running 5W40 in 5W20 and 5W30 engines lately and oil testing shows less iron&copper meaning better wear. Some companies like Amsoil and Redline will engineer a buttkicking 5W30 but the fact is any 5W40 you can find at Walmart is just as good if not better than a topline 5W30. So a cheaply made Group III 5W40 is just as good as any 5W30 produced by Amsoil or Redline. If your engine calls for 0W20 or 5W20 I wouldnt be afraid to go thicker like to a 5W30. I believe the difference is felt over 100000 miles. If you push your engine like towing or livery work or Subaru turbo aftermarket mods than no doubt 5W40 is the only oil to consider. In terms of HDEO vs Euro 5W40 I find that HDEO is generally thicker but both are thicker than 5W30. In terms of Amsoil/Redline Group IV/V vs cheaper made Group IiI 5W40s I think you can make it on the cheaper made varieties. The cheap 5W40s Ive found are: AmazonBasics Euro and HDEO (WarrennDistributing/Mag1/Supertech) API SN Chevron Delo API SN Plus Mobil Delvac 1 API SN Castrol API SN Mobil 1 Turbo Diesel Truck API SN Not included in the list is Shell Rotella T6 because lacks an API gas engine rating. All of these will be better than any 0w20, 5W20 or 5W30 out there. As for cold starting you will know when you need the better starting oils like 0W like if you live in Alaska, but I dont live in cold places where thats a concern...
 
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1,402
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Athens, GA
So, care to post your oil analysis that shows the lower iron and copper? Edit: Just now reading your UOA post. https://www.bobistheoilguy.com/foru...es-5290-veh-102308-2018-lincoln-navigato Basically, what you're saying is that in an Ecoboost motor, you've found that thicker is better. You can't make a sweeping statement like that for all engines. Certainly there are plenty of engines that might do better on a thicker oil, but there are plenty that just don't care. You'll get 300,000 miles out of them using 0W-16 or 5W-40 and probably not be able to measure any wear difference at the end. I'd almost have been willing to bet that your chain would have failed regardless, might have taken another 1000 miles but it would have failed just the same.
 
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3,498
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Chicagoland
My not so highly calibrated butt dyno says my engines that call for 5w20 like 0w40 better than 0/5w20, but in all honestly 0/5w20 is just fine for 99% of people. I drive them harder than most people though.
 
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Navi

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NYC
I post all of my UOAs in the appropriate section of the website and I do them every time I change oil. Each time Ive sent a sample to Blackstone I get glowing reviews. As well the engines I put 5W40 into seem to run better and amoother. There was a 5W20 engine that would clatter and now it runs smooth.
 
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2,266
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Seattle-ish, WA
"There is a theory which floats around on the internet that thinner oil circulates better around the engine during startup preventing wear " That's because advertising lies and uses differences at extreme temps ("cold"), like -10 to -15C differences, to convince you you need thin oil thickened out with polymers. Anyone who understands what "cold" means in oil testing knows this makes no difference if it's over 15F. The SAE paper showing the strongest correlation between reduced wear and oil film strength has not been disproven... (sorry not on my home computer to hyperlink it right now).
 

Navi

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NYC
Where I live we have 4 seasons. There is a winter with snow and ice but not an arctic cold winter. My cars start up just fine with 5W40. The oil analysis comes back just fine. Now if I lived in Alaska things might be different.
 
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Maricopa Arizona
Originally Posted by Oro_O
"There is a theory which floats around on the internet that thinner oil circulates better around the engine during startup preventing wear " That's because advertising lies and uses differences at extreme temps ("cold"), like -10 to -15C differences, to convince you you need thin oil thickened out with polymers. Anyone who understands what "cold" means in oil testing knows this makes no difference if it's over 15F. The SAE paper showing the strongest correlation between reduced wear and oil film strength has not been disproven... (sorry not on my home computer to hyperlink it right now).
https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/1478016/Re:_Attn_thick_oil_guys,20W50_ I believe this sums up the paper you are referencing.
 
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My 2017 Hyundai 2.4L GDI non - turbo engine calls for 5W20 on the oil fill cap - I have always run 5W30 synthetic in it . Just for grins , I decided to run QSUD 5W20 as my winter fill and what I have found 2,200 miles into the fill is : 1) A noisier engine 2) More oil consumption 3) No detectable increase in gas mileage 4) No detectable difference in how fast the engine warms up or accelerates ... On a warm enough day that makes me want to do an oil change - this QSUD 5W20 will be dumped between 3K to 4K miles and back in goes a 5W30 synthetic oil .
 
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Location
WA
Originally Posted by ChrisD46
My 2017 Hyundai 2.4L GDI non - turbo engine calls for 5W20 on the oil fill cap - I have always run 5W30 synthetic in it . Just for grins , I decided to run QSUD 5W20 as my winter fill and what I have found 2,200 miles into the fill is : 1) A noisier engine 2) More oil consumption 3) No detectable increase in gas mileage 4) No detectable difference in how fast the engine warms up or accelerates ... On a warm enough day that makes me want to do an oil change - this QSUD 5W20 will be dumped between 3K to 4K miles and back in goes a 5W30 synthetic oil .
Same engine in our Tuscon and I typically use 5W30 PP in winter and 10W30 M1 EP in the summer. Sometimes it gets left-over dino but nothing thinner than 5W30. Oil cap says 5W20. Car never seen a x20 except maybe the factory fill. In old days I used 10W40 in very cold places. It's good down to -12°F I prefer 10W40 (less vii) over 5W40 and I think 0W40 is a better oil than both unless you find a very good 10W40. If I had to use a xW40 it would be a 10W or 0W. To potentially avoid an inferior oil, you may have to buy a 0W40. Seems like xW20 is good for low(er) speed/rpm operation that average drivers encounter and preferably not much heavy towing in summer heat. I don't think manufacturers are that stupid to recommend an unsuitable viscosity for a little mpg gain. Having said that, I like to stay away from xW20. It hasn't grown on me yet! I have another 0W20 speced car that's getting 10W30.
 
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35,466
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NY
Originally Posted by ChrisD46
My 2017 Hyundai 2.4L GDI non - turbo engine calls for 5W20 on the oil fill cap - I have always run 5W30 synthetic in it . Just for grins , I decided to run QSUD 5W20 as my winter fill and what I have found 2,200 miles into the fill is : 1) A noisier engine 2) More oil consumption 3) No detectable increase in gas mileage 4) No detectable difference in how fast the engine warms up or accelerates ... On a warm enough day that makes me want to do an oil change - this QSUD 5W20 will be dumped between 3K to 4K miles and back in goes a 5W30 synthetic oil .
No harm in trying. It sounds like a good case for you to stick with 5W30 to me. I'd be doing exactly the same thing if those were my observations.
 
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954
Location
Alberta
I have run 0w40 castrol in my 2016 since the first oil change at 500 miles. No clatter at start and tows 7000lbs through the Rockies without fuss. I'll stick with a 40 weight. Picked up some 5w40 PP euro on sale recently as there seems to be a phasing out of the castrol at Canadian tire. Will try that when I run out of the castrol. The other factor that should considered is the quantity of soot produced by the twin turbo direct injection engines that are too small for filters, but are shown to damage chains. An increased oci is really the only way to remove those particles.
 

Navi

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467
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NYC
I have a Lincoln MKT with the 3.7 liter Duratec engine. Brand new, right from the factory there was a bit of noise in the engine. It sounded like lifter tapping. It wasnt horrible but it didnt seem like how a new Lincoln should be. When I put in 5W30 it eliminated that noise. Then when I went to 5W40 it really refined it. No noise and just buttery smooth. In Europe they use 5W40 in many applications. Mercedes S class for example. You dont hear any engine noise out of the S class... In general when I hear noise, especially metallic noise, out of an engine it just seems to me it never leads to a good outcome.
 
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35,466
Location
NY
Originally Posted by Navi
In general when I hear noise, especially metallic noise, out of an engine it just seems to me it never leads to a good outcome.
thumbsup I agree, metal isn't supposed to be banging against metal inside an engine.
 
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1,058
Location
Minnesota
I've read a number of statements over the years about people living in '4 season' areas and that 'the car will start' with thicker oil in winter. Gee, with modern well timed high energy ignition and well metered fuel injection, they will certainly start and run. A goal is adequate lubrication protection as quickly and much as possible. A single type and grade that will do that year around can get difficult for somebody in the northern tier much less Fairbanks. I'm talking about starting in temps of -30 to -40F. Since fully warmed engine coolants are designed to be running around 200F I can figure that the engines can live with an 0-20, but I do question the full possible engine longevity with blazing summer heat, adding heavy working loads, hard driving (maybe long timing chains?)with having enough 'cushion'. There have been drivetrain changes over the years that are usually more pointed towards manufacturing savings and emissions than improvements for longevity that seem to be a mixed bag to me. We are usually the proving ground where we find out if the improvements really are or aren't. Anyway, another other part is helping with the winter starts. I've generally used block heaters to help the engine 'think that it's summer'. A 55 year old Buick still has it's early installed 1200W tank heater type-a real cooker. I also still have in my head testing of years ago that showed increased cylinder wear below 160F. So, I want the engine to get there as quickly as possible before putting it to much work. My wife loves her remote starts and heated seats/steering wheel and so do as I also think about the engine temp before driving off. Anyway, while I will run 5-20 syn in winter, in summer it's generally 10-30. Carry on-
 
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Location
Jupiter, Florida
At my NY hangar, I have to start the car, leave the parking lot and immediately accelerate to 65MPH without cutting off other drivers. Two problems with that. First, I'm not allowed to let the car idle and warm up. Second, thick oil prevents the engine from performing this task on zero degree days. There is no question that a quality synthetic of adequate viscosity is the proper choice here. 5W-30 M1 works very well in the winter. 5W-40 TDT or 10W-40 M1 HM work very well in the summer.
 

Navi

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467
Location
NYC
That is a good question...you dont hear too much about 10W oils nowadays...its all either 5W or 0W...do any cars call for 10w anymore? I remember a while back in the 80s or 90s when I saw 10W30 as a suggested viscosity but at some point it disappeared and I am guessing its because of CAFE.
 
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