Oil experts, please share your knowledge.

[Shel_B]

Here's another opinion about thinner oils. Jason is pretty well regarded, and has a connection with Mobil. I didn't read this entire thread as I've read enough of such discussions to have a good idea of the content. So, this link is for @Dimitrius James.

 

[Carlostrece]

Regarding OP post #1... I'd use 5w20 if I had a Rav4. That's what my neighbor has in her CRV and it works well for her. i.e. - I'd go a bit thicker than 0w16, but not too much thicker. That's my opinion.

 

[Carlostrece]

I just bought 5w20 Quaker State High Mileage Full Synthetic for my neighbors 03 Honda CR-V. That oils runs slightly on the thick end of 5w20, which is perfect, IMO.

Quaker State Ultimate Protection Full Synthetic runs quite a lot on the thickend for 5w20. If I was going to use Quaker State Ultimate Protection Full Synthetic for her CR-V then I'd use 0w20.

Quaker State prices at Walmart are excellent.

I bought her a NAPA Gold oil filter because I think it's the best.

 

[lilspenny]

Hello all. First, please forgive me because this is going to be a bit wordy. I’ve been a long-time lurker and thought I’d finally join as I have a question/concern I was hoping to have answered. I know this question has been asked before, so forgive the redundancy, but It’s me asking the question this time, wanting to hear from those who have knowledge on the subject for my own edification.



So let me begin with some minor background on myself. I’m a former Ford heavy-line tech. I worked for a Ford dealership from the mid ‘90’s to mid 2000’s. I’m not saying that to profess any kind of vast knowledge as it’s been ~30 years since I’ve worked on cars professionally and a lot has changed in those years. I love working on cars for fun but got to hate doing it for a living. Working at the dealer sucked the fun out of it and the life out of me, but it does provide some context for the question I’m going to ask. That said, I’ve done maintenance and repairs for all the cars in my family in the intervening years as it’s still a hobby I enjoy, as I’m sure is the case with a lot of you here on BITOG. It’s probably the love of cars, and likely all things mechanical that led many of us to this web forum to begin with.



I suppose I can say that I’m looking for confirmation, affirmation, validation, and perhaps absolution lol. Anyway, when I was training in Ford’s program back then, when the engineer came in to teach us on “engine theory” or whatever it was called, when speaking about lubrication, he said something that stuck with me. He basically said that the oil viscosity doesn’t matter as much as the oil spec. In other words, if the motor calls for, for example, an API SP oil (not sure what it was back then, SH or SJ maybe?) then any API SP oil (or whatever API spec the engine called for) will be fine for that motor regardless of viscosity as it will have the additive package necessary to properly lubricate and protect the engine, and that viscosity selection should be based primarily on driving and climate conditions.



I’ve followed this advice since then and it’s never failed me. But, engines were less complicated back then. Variable valve timing systems such as BMW VANOS and Honda’s VTEC had only been introduced a few years prior and were still relatively new. Ford’s modular 4.6L SOHC engine and it’s self-grenading 5.4L big brother were still relatively new for Ford. More importantly, oil grades/viscosities were still fairly simple. You had the usual suspects for most passenger vehicles which were, of course, your 5w30’s, your 10w30’s and 40’s, and of course the 15 and 20w oils as well. I think Mobil 1 0w30 had just been introduced around this time, and was near impossible to find, so it may as well not have existed. Of course, this is mid-90’s so internet was still in its infancy as well.



Anyway, now we come to the meat of the matter, my reason for posting. We recently purchased a RAV4 Prime for my wife, which calls for 0w-16, and I will likely be purchasing the new ’26 for myself when they come out, which will no doubt “mandate” 0w-8, despite having the same power train (or so I’ve heard). I have a hard time wrapping my head around these water thin oils. I’ve been educating myself here on this board, reading about cSt’s, HTHS, TBN etc., comparing the w-8, w-16, w-20 oils to the more traditional viscosities, and don’t like what I see. Maybe, maaaybe I can wrap my head around a w-20. For those who don’t know, all the hybrid Rav’s are built in Japan, and are both a U.S. and JDM car, so for giggles, I went to the Toyota Japan website and downloaded the owner’s manual for my wife's car. It’s in Japanese of course, but Google translate is your friend. Unlike the U.S. manual which states “must use” 0w-16 , the Japanese manual states that 0w-16 is recommended for best fuel economy, but that the engine is also “compatible” with 0w-20, 5w-20, and 5w30 motor oils, the caveat being that they meet API SP or Ilsac GF6A specs. Kinda what the old engineer was teaching us in our class back 30 years ago.



I’ve been on various Toyota forums, but they aren’t much help. The conversations usually devolve into people stating that you must use what’s stated in the manual because the engineers designed the engine only to run on that oil, and that the oil pump is electronically controlled and programmed specifically for that oil and so on. If you read far enough through these threads, you start to see pretty quickly that most of these individuals, as well intentioned as they are, know little about cars. I’ve researched it to death, and the pump is actually a chain driven mechanical pump. The only “electronically controlled” aspect of the lubrication system is an oil pressure control valve, which from what I’ve read in various places is regulated by the ECM via info provided by oil pressure and temperature sensors in the engine. I think this myth was started by the Car Care Nut. I love his channel and am a subscriber, but even he contradicted himself in this statement in a later video when he’s tearing down one of these engines and he points out the chain driven pump.



Anyway, I guess that I’ve answered my own question, but wanted to ask those of you who know as I’ve been out of it for so long. Was the old engineer right? Will I be ok using any viscosity as long as I stick with the proper API/Ilsac spec? If that’s the case, I will probably go with a 0w30 since I want to ensure our cars last. Her last car was 12 years old when we traded it in, and mine is about that age now. We typically keep our vehicles for at least 12-15 years and want to ensure these last at least as long.



Your input and knowledge are much appreciated.

I bought a new 2013 v6 Accord and ran nothing but 0w40 Mobil 1 and changed the oil every 5k miles. Traded the car when the mileage was100k for a new truck. At that time the Accord was not using any measurable amount of oil that I could tell. My wife now owns a 2019 RDX with 90k miles. I have been using Amsoil 0w20 in the winter and Ultra Platinum 5w30 in all other seasons, changing every 5k miles. No easily measured oil consumption there either. I have always looked for signs of oil usage, but haven't noticed any. Common sense goes a long way toward engine longevity. In my truck I have always used the indicated 5w30 except for heavy hauling trips in the summer. Then I've used 5w40. No way would I, if I had a new Rav 4, use 0w20 in summertime. No way would I use 0w8 at all, ever. I may be showing my age, 68, and some people might consider my practices similar to a loaded cannon rolling downhill in a crowd of people. But... so far things have worked out ok for me. Btw, I live in northern Alabama.

 

[Carlostrece]

I've changed my mind about using 5w20 in my neighbors Honda CR-V because her CR-V is a bit of an oil burner I have learned. So next time I'll put 5w30 in it.

 

[RMaybeth]

What i hear you saying is: "I want to use the best oil so my car lives the longest but there is too much information and I'm confused about what oil I should actually use."

I felt the exact same way when i first got my 2017 Lexus LS 460. It has 69,500 miles when I bought it in May 2023 but that didn't matter really, because I did what I always do when I get another new-to-me car: I assumed the previous owner was the world's biggest cheapskate as well as the laziest, and never maintained a thing on it. So the first thing, of many, to do to it was an oil change. But what oil?

While lurking in several car forums, including this one, I read about this supposed miracle oil in a bottle i.e. Pennzoil Ultra Platinum (not to be confused with "Pennzoil Platinum"). After reading comments and posts by people who raved about how great this stuff is, I decided to use Ultra Platinum for a while. Since the big V8 on this car takes almost two gallons of oil, it was not exactly a cheap decision either, especially since I had no intention of driving even halfway to Lexus' "recommended" 10,000 mile interval. (After working in automotive around 50 years, professionally and otherwise, and torn apart scores of engines, I firmly believe the brand of oil you put in is not nearly as important as how frequently you change it).

But now having picked the brand, it was the choice of viscosity that was in question. And for a while I just unquestioningly used Lexus' "recommended" 0w-20 weight oil - after all, they built the car, right? Why would they steer me wrong? But about a year into ownership, I read something that made me question that.

On a Lexus forum, another LS 460 owner, who lives and drives in Ireland, had noticed a significant difference in his (Irish) owner's manual, and the owner's manual for cars sold in the USA. He was wondering why his Irish owner's manual essentially said, it was ok to use any weight of engine oil appropriate for conditions. So for summer you can use 5w30 or even 10w-50 weight oil if you wanted or needed to. Meanwhile the American manual stressed "use 0w-20 always, period, full stop! You can use as heavy as 5w-20 oil in a pinch, but if you do, you must - MUST change it right back to a zero weight oil at the next oil change." So the forum poster was curious - why would Lexus recommend 5w30, 10w30, or even 10w-50, in one country - and in fact Lexus recommends this in every country EXCEPT the USA - but not for American owned cars?
Then an oil expert on the same forum explained, the automakers were so hamstrung by American regulations and requirements, the 0w-20 oil was recommended solely to help the car to meet the government MPG requirements. Yep, Lexus was forced to require zero weight oils in their engines, as if the (miniscule, at best) difference in MPG between a 0w-20 oil and 5w30 will somehow increase the car's MPG just a little!

And that was when I switched to 5w30 in this car. (And the idle is noticeably smoother too, whatever that's worth). My whole point being, the days of simply trusting the manufacturer's recommendations on maintenance items, are over. Especially when it comes to maintenance intervals - for most items, the "recommended service intervals" are much too long. Any carmaker, or anybody else for that matter, who actually claims "your auto transmission fluid never needs to be changed" is somebody who says things that should not be taken at face value.

 

[kschachn]

What i hear you saying is: "I want to use the best oil so my car lives the longest but there is too much information and I'm confused about what oil I should actually use."
I felt the exact same way when i first got my 2017 Lexus LS 460. It has 69,500 miles when I bought it in May 2023 but that didn't matter really, because I did what I always do when I get another new-to-me car: I assumed the previous owner was the world's biggest cheapskate as well as the laziest, and never maintained a thing on it. So the first thing, of many, to do to it was an oil change. But what oil?
While lurking in several car forums, including this one, I read about this supposed miracle oil in a bottle i.e. Pennzoil Ultra Platinum (not to be confused with "Pennzoil Platinum"). After reading comments and posts by people who raved about how great this stuff is, I decided to use Ultra Platinum for a while. Since the big V8 on this car takes almost two gallons of oil, it was not exactly a cheap decision either, especially since I had no intention of driving even halfway to Lexus' "recommended" 10,000 mile interval. (After working in automotive around 50 years, professionally and otherwise, and torn apart scores of engines, I firmly believe the brand of oil you put in is not nearly as important as how frequently you change it).

But now having picked the brand, it was the choice of viscosity that was still in question. For a while I just unquestioningly followed Lexus' "recommended" 0w-20 weight - after all, they built the car, right? Why would they steer me wrong? But about a year into ownership, I read something that made me question that.

On a Lexus forum, another LS 460 owner, who lives and drives in Ireland, had noticed a significant difference in his (Irish) owner's manual, and the owner's manual for cars sold in the USA. He was wondering why his Irish owner's manual said it was ok to use any weight oil appropriate for conditions. So for summer you could use 5w30 and even 10w-50 weight oil if you wanted or needed to. Meanwhile the American manual stressed "use 0w-20 always, period, full stop! You can use as heavy as 5w-20 oil in a pinch, but if you do, you must - MUST change it right back to a zero weight oil at the next oil change." So the forum poster was curious - why would Lexus recommend 5w30, 10w30, or even 10w-50, in one country (and in fact Lexus recommends this in every country EXCEPT the USA) but not for the USA?
Then an oil expert on the same forum explained, the zero weight oils were only used to meet government MPG requirements. And the automakers were so hamstrung by the regulations, the 0w-20 oil was factory fill, only to help the car to meet the government MPG requirements. Yep, Lexus was forced to require zero weight oils in their engines, as if the (miniscule, at best) difference between a 0w-20 oil and 5w30 would somehow increase the car's MPG just a little!

So after that I started using 5w30 in this car. And the idle is (probably) noticeably smoother too. Point being, we have reached a point in time where you can no longer simply trust the manufacturer's recommendations anymore, for anything to do with your car's maintenance.

Those aren't "zero weight" oils. You're not understanding how grades work.

 

[WDH]

I'm late to this thread, but the OP's question about the importance of viscosity is answered in the hydrodynamic and fluid flow equations of Isaaic Newton and Osborne Reynolds, with contributions from Heinrich Hertz and AN Grubin.

If you good at math and work at it you will know that these scientific giants answered the importance of viscosity in lubrication.

The problem is that the lay public can't do such math, and the engineering researchers are generally unaware and/or too lazy to do the math.

So lubrication is reduced to "art" rather than the science which it actually is.

You will have noticed that I have not answered the OP's question about the importance of viscosity. I'm leaving the assignment to the reader to work it out for themselves. It's the only way readers will know the answer with satisfactory confidence.

 

[GI_GRIFF]

0W-8 and 0W-16 are very shear stable viscosities. Companies like Mobil 1, who blend these, use mPAO and other expensive base oils to achieve such shear stability. I'd argue that you could run 0W-16 in many applications that call for 0W-20 without any ill effects.

But that's where my optimism ends.

These types of discussions usually start with: "As tolerances get tighter... thinner oils are used."

When in fact they should read: "As engine manufacturing becomes more precise, exotic coatings are used in more and more places, along with iROX coated bearings, more durable timing chains, etc, oil viscosities are lowered to eliminate as much parasitic drag on the oil pump as possible. Some manufacturers even use electric oil pumps to help the situation further..." - and so on.

And here lies the problem: you have to trust the manufacturer and their entire supply chain that no mistake was made, no corner was cut, because with thinner oils, you have less margin for error.

Just look at the recent GM L87 6.2L V8 engine recall: as a stop-gap, GM switched from 0W-20 to 0W-40 in engines that aren't yet damaged, to increase the oil film thickness inside the bearings so that the manufacturing imperfections don't rear their ugly head.

Conclusion: If you don't trust the manufacturer who's vehicle you bought, use a thicker oil. Use your noodle, and don't go overboard on the viscosity and oil type you choose. Too much can be just as bad as too little.

This is the difference between a person that actually knows something and a big dummy like me with my opinionated, uneducated, ideals. I will stick to my little higher 5W-30 viscosity in my Toyota recommending 0W-16. Obviously, it is just an emotional "old man" thing with me using the heavier oil. My 5W-30 I guess is my "feel good" blend and also ok with my Toyota people where I bought the car. Thanks for the education @lakestone

 

[Durdude]

I recently saw a Lake Speed video where he talked about the lower viscosity oils and wear protection. He sumarrized that 0w20 and 5w30 both show good wear protection based on his UOA data with Speed diagnostics. He commented on importance of keeping up on oil changes. All my cars are old and take 5w30. But my friends Subaru takes 0w20. Often people run the 0w30 or 5w30 mobil 1 ESP so I wonder if I should put that in the Subaru??? California car so mild weather. Can get hot over 100 in summer.

 

[SOUNDMAN5000]

For someone who purchased his first car in the 80's and at 16 started using a RACING 20w-50 oil as "thicker" and "racing" must be better right? Heck, I was uneasy when Ford moved from 5W-30 to 5w-20 in my 4.6L crown Vic 25+ years ago so the "0" oils as a older guy don't give me that warm, cozy feeling as I question is a super thin oil better for my new car or better for a gas MPG ( CAFE ) EPA requirement?

Are these thin oils designed to actually offer better engine protection with more modern / Hybrid engines?

With the recent announcements of a possible ease of Stop Start and other EPA , CAFE, requirements, the GM thin oil issue etc any chance these thin oils used in the US market new cars may become a bit thicker in the years to come?

 

[kschachn]

For someone who purchased his first car in the 80's and at 16 started using a RACING 20w-50 oil as "thicker" and "racing" must be better right? Heck, I was uneasy when Ford moved from 5W-30 to 5w-20 in my 4.6L crown Vic 25+ years ago so the "0" oils as a older guy don't give me that warm, cozy feeling as I question is a super thin oil better for my new car or better for a gas MPG ( CAFE ) EPA requirement?

Are these thin oils designed to actually offer better engine protection with more modern / Hybrid engines?

With the recent announcements of a possible ease of Stop Start and other EPA , CAFE, requirements, the GM thin oil issue etc any chance these thin oils used in the US market new cars may become a bit thicker in the years to come?

The oil’s winter rating has nothing to do with that. There are no “0” oils as already discussed in this thread

And as far as thick vs. thin discussions (complete with a side of CAFE and EPA) this board is replete with numerous and extensive threads. You can’t hardly keep from bumping into them.

 

[SOUNDMAN5000]

The oil’s winter rating has nothing to do with that. There are no “0” oils as already discussed in this thread

And as far as thick vs. thin discussions (complete with a side of CAFE and EPA) this board is replete with numerous and extensive threads. You can’t hardly keep from bumping into them.

Come on, I'm not a new poster asking what is the best oil to use or anything... I simply would like to know from some of you fine folks using these new Toyota spec oils that are as posted above 0w-16 in japan or but 0w-8 in the USA Is that 0W-8 because its in the USA market?
With the recent news this week with ease of EPA does someone have a opinion as to will we see the oil cap with 0w-8 printed on top change to 0W-16 on US Toyotas in the future... Forgive my questions if it offends...

 

[tired]

Was the old engineer right? Will I be ok using any viscosity as long as I stick with the proper API/Ilsac spec?

No. There are a lot of differences among the different oils of the same viscosity.

Just run Valvoline Restore and Protect 5W-30 from new, and you won't have any issues.

 

[kschachn]

Come on, I'm not a new poster asking what is the best oil to use or anything... I simply would like to know from some of you fine folks using these new Toyota spec oils that are as posted above 0w-16 in japan or but 0w-8 in the USA Is that 0W-8 because its in the USA market?
With the recent news this week with ease of EPA does someone have a opinion as to will we see the oil cap with 0w-8 printed on top change to 0W-16 on US Toyotas in the future... Forgive my questions if it offends...

Then as a veteran poster you should know the answer to all of that. It's been beat to death multiple times in multiple ways in multiple threads.

Thinner oils only reduce fuel consumption as a benefit.