In Light Driving Conditions Would You Notice Difference in 5w-20 vs 0w-30 - Subaru BRZ

[Revving2Redline]

If it were mine ESP 0W30 would be in it.

Any downfalls of using this? Safe for GDI engines? I know its higher hths than most standard 5 & 0w30.

 

[Patman]

Thank you for all of the replies on this. Yeah my light driving conditions made me wonder if 5w20 would be almost as good as a 0w30. The car will only be lightly driven, and my track days are behind me. Our climate can get pretty hot for about 2 months of the season, spring and fall months can be on the cooler side. I might start it up a couple times in winter months if I am moving it around,

Do not start the engine during that time period unless you are going to drive it and get the oil fully up to temperature. One of the biggest mistakes that people make during winter storage of cars is to periodically start up and idle the engine. It does more harm than good.

 

[kschachn]

Any downfalls of using this? Safe for GDI engines? I know its higher hths than most standard 5 & 0w30.

It works just fine in my Tiguan with GDI.

 

[zeroptzero]

Do not start the engine during that time period unless you are going to drive it and get the oil fully up to temperature. One of the biggest mistakes that people make during winter storage of cars is to periodically start up and idle the engine. It does more harm than good.

Thanks Patman, I think I can likely keep the car out of operation for next winter. I brought it home a few weeks ago and I've had to move things around as my garage is super tight and jammed with crap. I did take it out to bed-in some new brake pads I swapped in , and got the oil up to temp pretty good, but yeah hopefully it doesn't get started much more until it goes in regular use. Thanks for the tip.

 

[zeroptzero]

And another thick vs. thin thread, this one with a side of Amsoil and a dash of "warranty concerns".

well yes that is true. But I also wanted to note how my driving conditions factor into the entire comparison. It is thin vs. slightly thicker, but the vehicle and how it is driven is also part of my question. Many owners of this vehicle push it to its limits and many people end up on a track with it, I know that I won't . Also questions related to Amsoil itself and warranty etc. I appreciate all of the replies.

This site like all other forum needs new posts to keep it moving along, more posts = more traffic, traffic keeps forums alive and kicking.

 

[zeroptzero]

He has legitimate questions. Things change over time, so the age old thick vs thin doesn’t always apply. If it did, there would be no reason for this forum.

I agree, thank you.

 

[demarpaint]

Any downfalls of using this? Safe for GDI engines? I know its higher hths than most standard 5 & 0w30.

The specs are published, I don't have them handy. I see no downside. Opinions will vary.

 

[Hohn]

With my 2024 Subaru BRZ it runs a 0w-20 oil from the factory and as the recommended oil. I have it in winter storage right now with only 200 kms on it. It will go on the road in May as a weekend only garage queen car. I have a daily driver that I use for work, and I just want a weekend toy to putz around during warm weather months (3 seasons). It will be driven easy, not pushed hard at all, and no track use, I won't likely drive it in the rain. I expect to do one oil change per year, which should be plenty for a low mile vehicle.

I bought a stash of Amsoil 5w20 recently as it was on sale at a store going out of business, I have enough to last me for the 2025 season. I wanted to do 5w20 for the lower NOACK numbers, it is a pretty decent difference compared to 0w-20. If I go to 0w-30 the NOACK numbers increase from 5w20.

I was considering 0w-30 to potentially lower engine wear but the operative word is "potentially". On a car that is driven lightly in optimal ambient conditions would there be much wear difference between 5w20 or 0w30 ? Obviously the engine isn't going to die off just from running a 20 weight oil , but would there be much wear difference between 0w-30 or 5w20 ? I could run 5w30 to get the NOACK numbers back down, so that is an option, but if the wear difference is small I might be okay with 5w20 this year. I do have a chance to buy more of the discounted oil which would cover me for 2026 if I bought it now while on sale, I just have to decide if I want to buy more of the 5w20 or wait to run a 30 weight.

Thanks for reading , and any opinions on this

The car is brand new and will never be driven hard. The 0w-20 oil if perfectly fine for both warranty preservation and engine preservation.

The lower tension oil rings in newer engines can struggle to scrape thick oils from the walls very effectively. This can drive a bit higher consumption at low loads and modest temperatures.


I think your case is a poster child for HPL 10w20 oil. The car will never see cold starts, needs the lowest practical volatility and has no need to viscosity over 20 grade because it won't be run hard or hot.

 

[zeroptzero]

The car is brand new and will never be driven hard. The 0w-20 oil if perfectly fine for both warranty preservation and engine preservation.

The lower tension oil rings in newer engines can struggle to scrape thick oils from the walls very effectively. This can drive a bit higher consumption at low loads and modest temperatures.


I think your case is a poster child for HPL 10w20 oil. The car will never see cold starts, needs the lowest practical volatility and has no need to viscosity over 20 grade because it won't be run hard or hot.

Thanks for the added information and there are many components to this application as you noted. I will search up HPL, I am not familiar with it, and being a new member here I have not researched it up to this point in time. I am ultimately looking for a long term oil to use so the more options the better, and I have some time to make any change if needed, so I thought it was worthwhile asking ahead. Thanks.

 

[Leo99]

He has legitimate questions. Things change over time, so the age old thick vs thin doesn’t always apply. If it did, there would be no reason for this forum.

You assume facts and data would override people's deeply held beliefs and opinions.

 

[zeroptzero]

You assume facts and data would override people's deeply held beliefs and opinions.

This forum would have very little exchanges of questions and answers if people did not include beliefs and opinions in their selection of motor oil. Also the facts are never really 100% , there is always an interesting spin on what people report as facts. I like asking questions and getting replies from all sides of the issue, then we can make our decision whether it is based on beliefs or facts. This seems to work great IMO.

 

[Leo99]

This forum would have very little exchanges of questions and answers if people did not include beliefs and opinions in their selection of motor oil. Also the facts are never really 100% , there is always an interesting spin on what people report as facts. I like asking questions and getting replies from all sides of the issue, then we can make our decision whether it is based on beliefs or facts. This seems to work great IMO.

I'm just poking fun. Part of my career is being a data scientist. The empirical data tells the story. It's my belief that your engine is not going to know the difference between 5w-20 and 0w-30.

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[Glenda W.]

The lower tension oil rings in newer engines can struggle to scrape thick oils from the walls very effectively. This can drive a bit higher consumption at low loads and modest temperatures.

This statement caught my attention because I was taught in engine classes that thicker oil creates a better seal causing less oil consumption. Which also aligns with my experience running both thick and thin oils in my oil burner. Thicker oil equals less consumption. Curious where you heard this?

 

[kschachn]

The lower tension oil rings in newer engines can struggle to scrape thick oils from the walls very effectively. This can drive a bit higher consumption at low loads and modest temperatures.

So you're saying that an engine with low tension oil rings consume more oil if I use a higher grade? How high?

My Tiguan has low tension oil rings I believe, but it consumes less of a Euro 30-grade than it does a 20-grade. I just don't see it.

 

[zeroptzero]

I'm just poking fun. Part of my career is being a data scientist. The empirical data tells the story. It's my belief that your engine is not going to know the difference between 5w-20 and 0w-30.

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That's the kind of answer I need, lol, very good , thank you. I just read that everyone invests a lot of time and money on UOA's and then you turn around and read opinions that UOA's don't really measure the real wear of an engine, blah , blah , blah, so facts are hard to come by. Facts are good, I just don't know when I am getting them or not.

 

[TiGeo]

That's the kind of answer I need, lol, very good , thank you. I just read that everyone invests a lot of time and money on UOA's and then you turn around and read opinions that UOA's don't really measure the real wear of an engine, blah , blah , blah, so facts are hard to come by. Facts are good, I just don't know when I am getting them or not.

The facts that many here that use higher viscosity oils vs. what the manufacturer recommends rely on are tribological/engineering studies that show that higher viscosity oils = more protection, it's not really debatable. But you are correct, the UOAs while interesting, don't tell you much about wear comparing oils as much as we all want that to be. While all this is well and good and folks can clearly do whatever they want/comfortable with, the variation of using a 20 to 30 grade oil (which seems to be what the typical "thick/thin debate" is about) w/r to real-world wear impacts (running issues, oil consumption, excessive wear causing low compression etc. etc.) on a modern engine used "normally" isn't material in my opinion. There are so many examples have been posted here of vehicles running to high milealage/many years on 20 grade oils (I have one) without anything noteable...but yes, they will have more wear (whatever impact that actually has, if any) per the previously referenced studies.

 

[kschachn]

That's the kind of answer I need, lol, very good , thank you. I just read that everyone invests a lot of time and money on UOA's and then you turn around and read opinions that UOA's don't really measure the real wear of an engine, blah , blah , blah, so facts are hard to come by. Facts are good, I just don't know when I am getting them or not.

The biggest issue is that a UOA is an uncontrolled environment to isolate the wear due to the oil. There are many outside influences on a simple spectrographic analysis of an oil. Often we see two UOA with two different oils and unwarranted conclusions are drawn that one oil produces less or more wear than another. That sort of determination is utterly impossible by comparing two analyses such as this. Comparative wear analysis between oils is complicated and expensive due to the requirement of obtaining statistically significant data that isolates the one variable of the oil.

 

[Propflux01]

You assume facts and data would override people's deeply held beliefs and opinions.

Sometimes facts and data simply do not jive with real world results. I assume nothing.

 

[kschachn]

Sometimes facts and data simply do not jive with real world results. I assume nothing.

That’s extremely rare despite many thinking it’s more common. Often “real world” results are so clogged with bias and assumptions that once they are properly analyzed do not yield the conclusion first assumed.

People draw conclusions based on bias and assumption on many things. The term is “illusory correlation”.

Facts should always correlate to any observation.

 

[VolkswagenFox21]

Subaru Japan used to recommend 0w30 and 5w40 for the first gen BRZ and they still recommend 0w30 for current gen models. http://www.pleiades-zero.com/?page_id=342

"Perfect for BRZ"

Toyota Australia also mentions 5w30 as a recommended viscosity in the owner's manual for the GR86.

Subaru and Toyota are both fine with higher viscosity oils in these cars. Personally, I switched to euro 30 or 40 weight oils in my FRS a year after I bought the car.