0W20 vs 5W20 base oils

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Dec 30, 2006
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Do 0W20 oils always have higher quality base oils vs 5W20 oils (as I've read on here before)? Or is this a myth?
 
No myth. Harder specs to reach nowadays in the thin grade and it could be why Motorcraft Semi-syn 0w20 in SN Plus GF5, will step-aside for 0w20 Motorcraft Full Synthetic in SP /GF6.
Just a guess, based on gossip I read online. There's been a few 0w20 synblends available. But for how much longer? Specs get tougher and the conventional and synblends can't seem to keep up. It was nearly impossible to find any conventional 5w20/30 in Dexos 1 Gen 2 SN Plus.
 
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It is irrelevant. Any claims to base oil quality are hypothetical and academic, but do not have material tangible evidence.
I would look at specifications first. Tougher specifications will require better formulated oils.
The fact that some of the newer specs are centered on 0w20 and 5w30 may influence things but in brand lines that include 5w20 and 10w30 with the aforementioned viscosities, there is no reason to suspect any difference other than viscosity modifier and amounts of base oil of certain viscosities. .
 
I think OEM's that moved to 0w20 are working the odds that often it does. That's not to say ST 0w20 is better than Amsoil SS 5w20 … but from the same company … ? Most likely …
 
I am glad someone made this thread as I was just thinking about this the other day after having experimented for the first time using a synthetic 5w20 in an engine that requires 0w20. I think it will be my first and last time filling my sump with synthetic 5w20. Here is what I posted on another website:

I wanted to post a reflection on using synthetic 5w20 for two weeks and 1000 miles in my 2018 Outback 2.5L engine with 100,500 total miles on it now. Of note the weather has been very hot and humid by local standards, 90 degrees fahrenheit.

A few things I have noticed are that my engine is running much louder and hotter than it ever has as a recall when I have used 0w20 in the past. With 0w20 the oil temperature was on average around 210-215 degrees normal warmed up operating temperature. With 5w20 it has been at least 10 degrees higher, anywhere between 220-230 degrees. I have also noticed a little more start up noise that sounds like timing chain clatter but it only lasts for a second or two but it is noticeable to my ear, this could just be a timing chain in need of a tensioner though.

So like with the experiment in which I tried out using a 5 quart jug of 5w30 during my last oil change interval, I will probably just be running 5w20 one time and then go back to using 0w20 noting any differences. I have a jug of Mobil 1 EP 0w20 and eleven quarts of Valvoline Synthetic Maxlife 0w20 on deck.

Again I am not knocking the usage of 5w20 but at this time I choose to use it on an experimental basis to gauge the results, for this car/engine it had much do with an oil consumption issue it has developed that I am tracking.
 
thinner oils are LESS stout than say the common 5-30 of the same class, so to meet specs better $$$ base oils are needed, BUT remember these are tested NEW + likely decline faster being thinner overall. NO anything xxW20 for me because less wear is more important than minimal MPG increases!!
 
You are in good oil quality hands for the future.. Vehicle engine noises occur as the engine ages. So many here think highly of Rotella T6 Gas-Truck quieting their engine.
Others (me) say supplements like Biotech and MoS2 quiet things too. Perhaps troubleshoot the noise yourself using Gas-Truck with Biotech and let us know if it returns your engine sounds back to new condition.

If not, then wait for worsening sounds and seek a mechanic for advice.
 
If you are having engine noises with only 100,000 miles and have been running thin syn oils. You are getting exactly what you deserve. You need to quit believing all the marketing crap that they keep telling you.
 
Originally Posted by aquariuscsm
Do 0W20 oils always have higher quality base oils vs 5W20 oils (as I've read on here before)? Or is this a myth?


Will likely vary blender to blender. With XOM, if we can trust the MSDS sheets, then yes, there's a clear correlation with the 0w-20's in AFE, EP and AP all having significantly more PAO than the 5w-20's.

Regular M1:
[Linked Image]

[Linked Image]


M1 EP:
[Linked Image]

[Linked Image]


M1 AP:
[Linked Image]

[Linked Image]
 
Originally Posted by 77Se7en
You are in good oil quality hands for the future.. Vehicle engine noises occur as the engine ages. So many here think highly of Rotella T6 Gas-Truck quieting their engine.
Others (me) say supplements like Biotech and MoS2 quiet things too. Perhaps troubleshoot the noise yourself using Gas-Truck with Biotech and let us know if it returns your engine sounds back to new condition.

If not, then wait for worsening sounds and seek a mechanic for advice.


For reference I had used Rotella Gas Truck for the previous 25,000 miles or so worth of oil changes at 6000-7000 mile intervals. The first three used RGT 0w20 and went fine, with a quieter engine, until I noticed an oil consumption issue developing during the last OCI. Having a spare jug of RGT 5w30 I decided to try that out and it made the engine run sluggish.

I got a good deal on two jugs of Valvoline Synthetic Maxlife 5w20 at Walmart for $10.88 each and decided to try it out after I dumped the RGT 5w30 and initially everything was fine but as more time and miles have gone by more the increase in engine noise has picked up as well as operational temperature.

Originally Posted by rideahorse
If you are having engine noises with only 100,000 miles and have been running thin syn oils. You are getting exactly what you deserve. You need to quit believing all the marketing crap that they keep telling you.


I never noticed any issues until I used synthetic 5w20. The oil I used that increased engine noise the most was Mobil 1 AFE 0w20 but even that was nothing compared to synthetic 5w20.

I have not had any issues using 0w20 in my Subaru or Hyundai GDI to date other than an oil consumption issue with the Subaru that is Subaru openly acknowledges in the owners manual.
 
Originally Posted by Ignatius
. I think it will be my first and last time filling my sump with synthetic 5w20. Here is what I posted on another website:

I wanted to post a reflection on using synthetic 5w20 for two weeks and 1000 miles in my 2018 Outback 2.5L engine with 100,500 total miles on it now. Of note the weather has been very hot and humid by local standards, 90 degrees fahrenheit.

A few things I have noticed are that my engine is running much louder and hotter than it ever has ..... I have also noticed a little more start up noise that sounds like timing chain clatter but it only lasts for a second or two but it is noticeable to my ear, this could just be a timing chain in need of a tensioner thoug

Again I am not knocking the usage of 5w20 but at this time I choose to use it on an experimental basis to gauge the results, for this car/engine it had much do with an oil consumption issue it has developed that I am tracking.

What filter did you run? The Subaru Blue? We have a FB2.0 and the TC is noisy most of the time at starts. It wasn' No Oil Consumption on the FB2.0 though.

This can be batch dependent also. I Have run same oil back to back with widely varying results.
I do think your perception is based on the ambeint temperature as it has a large influence on on sump temps.

Unless you keep a journal and record and chart trip ending temps on the same commute with same conditions

the perceptions are not validated. Notice I didn't say meaningless
smile.gif


If I had a 2.5 L engine I would be running 5W30.

You have the wrong oils.on Deck
smile.gif
Though the EP is not a bad choice.

Valvoline Advanced 5W30 was the best moderately priced synthetic out there last year that I have run, IMO

And I have UOA to back up this assertion - for argument sake.

Big problem with Subaru is their filter choice and OE service part manufacturer.

Maybe go to Mazda parts and buy a Fabrique' au Japon Mazda Tokyo Roki ( same OE as factory subaru ) and run that.

I have noted and validated that Subaru FB dry start every time after a short sit.. Empty filter can.

That will cause startup noise. That is not the lubricant's fault, but rather a very poor engineering/design choice.
On the Fuji engineers.

We in the U.S have historically designed the best Machines. Not Germany or Japan - Though You can argue Italian design with me.
They have some great stuff historically.

- Ken

.
 
Originally Posted by OVERKILL
Originally Posted by aquariuscsm
Do 0W20 oils always have higher quality base oils vs 5W20 oils (as I've read on here before)? Or is this a myth?


Will likely vary blender to blender. With XOM, if we can trust the MSDS sheets, then yes, there's a clear correlation with the 0w-20's in AFE, EP and AP all having significantly more PAO than the 5w-20's.

Regular M1:
[Linked Image]

[Linked Image]


M1 EP:
[Linked Image]

[Linked Image]


M1 AP:
[Linked Image]

[Linked Image]



Really interesting,thanks! The 0W oils look to be 70% pao base stock.
 
A little more sluggish 5w30 and 5k OCIs may be The Ticket here. I felt more sluggish jumping from 8.5 cst to 10.5. But the engine is quieter and silky-smooth with the new grade. I can deal with minutely less pep upon acceleration. I can deal with a temp gauge that now shows a decimal-advancement hotter. I've never taken a gauge to the oil temps. But many say hotter GDIs reduces carbon / soot. Not sure if that's true.
 
Originally Posted by ARCOgraphite
Originally Posted by Ignatius
. I think it will be my first and last time filling my sump with synthetic 5w20. Here is what I posted on another website:

I wanted to post a reflection on using synthetic 5w20 for two weeks and 1000 miles in my 2018 Outback 2.5L engine with 100,500 total miles on it now. Of note the weather has been very hot and humid by local standards, 90 degrees fahrenheit.

A few things I have noticed are that my engine is running much louder and hotter than it ever has ..... I have also noticed a little more start up noise that sounds like timing chain clatter but it only lasts for a second or two but it is noticeable to my ear, this could just be a timing chain in need of a tensioner thoug

Again I am not knocking the usage of 5w20 but at this time I choose to use it on an experimental basis to gauge the results, for this car/engine it had much do with an oil consumption issue it has developed that I am tracking.

What filter did you run? The Subaru Blue? We have a FB2.0 and the TC is noisy most of the time at starts. It wasn' No Oil Consumption on the FB2.0 though.

This can be batch dependent also. I Have run same oil back to back with widely varying results.
I do think your perception is based on the ambeint temperature as it has a large influence on on sump temps.

Unless you keep a journal and record and chart trip ending temps on the same commute with same conditions

the perceptions are not validated. Notice I didn't say meaningless
smile.gif


If I had a 2.5 L engine I would be running 5W30.

You have the wrong oils.on Deck
smile.gif
Though the EP is not a bad choice.

Valvoline Advanced 5W30 was the best moderately priced synthetic out there last year that I have run, IMO

And I have UOA to back up this assertion - for argument sake.

Big problem with Subaru is their filter choice and OE service part manufacturer.

Maybe go to Mazda parts and buy a Fabrique' au Japon Mazda Tokyo Roki ( same OE as factory subaru ) and run that.

I have noted and validated that Subaru FB dry start every time after a short sit.. Empty filter can.

That will cause startup noise. That is not the lubricant's fault, but rather a very poor engineering/design choice.
On the Fuji engineers.

We in the U.S have historically designed the best Machines. Not Germany or Japan - Though You can argue Italian design with me.
They have some great stuff historically.

- Ken

.


Well sir I will have you know that your Crosstrek UOA with Valvoline heavily influenced my decision to stock up on Valvoline 0w20, so thank you for having it done and posting it here
smile.gif


Oil filters by OCI:

1. Subaru OEM
2. K&N HP-1010
3&4. Fram Ultra XG7317 (two consecutive intervals)
Current: Fram Ultra XG7317
 
Originally Posted by aquariuscsm
Originally Posted by OVERKILL
Originally Posted by aquariuscsm
Do 0W20 oils always have higher quality base oils vs 5W20 oils (as I've read on here before)? Or is this a myth?


Will likely vary blender to blender. With XOM, if we can trust the MSDS sheets, then yes, there's a clear correlation with the 0w-20's in AFE, EP and AP all having significantly more PAO than the 5w-20's.

Regular M1:
[Linked Image]

[Linked Image]


M1 EP:
[Linked Image]

[Linked Image]


M1 AP:
[Linked Image]

[Linked Image]



Really interesting,thanks! The 0W oils look to be 70% pao base stock.


I remember reading Gokhan's post related to this about a year ago:

https://www.bobistheoilguy.com/foru...ly-alkylated-naphthalene-an-#Post5116575
 
Originally Posted by buster
Good post Overkill. That is correct.



+1
That's why I grabbed so much M1 AP on clearance for the DI engines …
I can use VME or RGT in the Pentastar …
 
What do we mean by higher quality base stocks? Film strength? Freezing start performance, flash point etc?
 
This is just my .02 but my 2005 Accord ran 5w20 its entire life and I didn't have any problems and once it hit ~200k miles I switched it to 0w20. Because I always heard that 0w20 had a better base oil, also Honda stated that the cars could be ran on it. The Accord is now at 240k miles and still run great. I don't believe in the dissent that thinner oils are 'killing' engines.
 
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