0W20 vs. 5W20 Synthetic In GDI Engine ?

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A number of newer vehicles with GDI engines state to use 0W20 as preferred and in areas where it can not be found up to 5W30 is acceptable (i.e. Mazda Skyactiv 2.0L) until you can locate 0W20 oil . I believe typically the synthetic 0W20 will have a higher NOACK value which in a GDI engine you would want to use the lower Noack 5W20 synthetic oil if you had a choice ? ... *Are OEM's of GDI engines (Mazda again) trying to ensure that with a 0W20 you will have to use full synthetic OR a synthetic blend at a minimum versus stating a 5W20 is also acceptable out of concern you will use a conventional 5W20 instead of a lower NOACK oil in a GDI engine ?
Also , if I have a GDI engine (Mazda) , I don't live in a very cold environment - then why wouldn't I want to use a 5W20 synthetic in my GDI engine and enjoy a lower NOACK that would aid in keeping intake valves cleaner than 0W20 with the higher NOACK ? Other than cold start protection I can't see a reason to use a 0W20 synthetic versus a 5W20 synthetic oil ... Your thoughts and experiences ?
 
with Hyundai/Kia GDI history stick with 3-5k OCI and I would use OE filter, it wouldn't matter Hyundai and Kia do fine on 5w30.

For Mazda, I would stick with a 0w20. I have a Mazda engine in my Scion IA and have had no problems switching from Mobil 1, Castrol Edge, Idemitsu, NAPA Full Synthetic which is rebranded Valvoline very good oil all 0w20.
 
I have a 2011 Kia Optima with the 2.4 litre engine. I use 5W30 in the summer and 5W20 in the winter. I run 10,000 km OCI with the OEM filter. I have never had any issues with the engine. Infact the issues I have had are two prematurely worn seat covers that were replaced under warranty. It has been a great car. I expect to keep it for another four years.
 
At one time I would have chosen 0w20 synthetic over 5w20 synthetic based on the idea that it must have some PAO (or at least 'more synthetic') in it to meet the '0' rating.
I'm now beginning to think that I would prefer a 5w20 full sythetic for the reasons you cite (lower NOACK etc)...especially if I lived in a warmer climate like Geogia... Valvoline Syn. 5w20 was claiming a NOACK under 8...nice.

PS: 0w20 or 5w20 synthetic...either one will keep your engine running for a long, long time.
The car makers probably spec. 0w20 so that owwners will be more likely to use synthetic (and not use a dino 5w20).
 
I use PPPP 5w-30 in my 2 Kias - very good oil with excellent cleaning capabilities.
Running Castrol Edge (GC) 0w-40 at the moment thou due to hot weaather and high car load for the past month.
 
Originally Posted By: Speak2Mountain
PP 5w-20
good NOACK ...
That's exactly what I'm doing in my 0W-20-specified car, for that (assumed) reason and the lower VII loading. This is near Georgia (and N.C.).
 
Amsoil SS 0-20 NOACK of 8.5. While their SS 5-20 is 5.8. That is quite a diff. between a 0 & a 5w. Of course we R talking 100% synth and not full synth. But w a GDI I may not be using a great oil for such a short OCI but...
 
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generally a xxW-30 will have better noack than a xxW-20 of comparable quality + in your area i would use a brand name 10W30 fake synthetic as most $5 a qt "synthetic" oils are today, group III highly refined + processed CRUDE oils!!! i like mobil I extended performance 10-30 said to have some real synthetic in the blend aka PAO. Mobil refines + makes ALL types of base oils!!! but like most will not say whats in any blend.
 
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In my Toyota owners manual is says to use 0w20 but that 5w20 is suitable to be used if 0w20 is not available but that I need to switch back to 0w20 at the next oil change. Then it goes on to list Mexico and says that 10w30 is acceptable.

I would use what they call for or as close as possible but it's not like the engine is going to blow up or anything. It just may not provide optimal results the OEM is looking for in terms of fuel economy or lubricity on certain conditions but these are minor in nature.
 
Originally Posted By: ChrisD46
A number of newer vehicles with GDI engines state to use 0W20 as preferred and in areas where it can not be found up to 5W30 is acceptable (i.e. Mazda Skyactiv 2.0L) until you can locate 0W20 oil . I believe typically the synthetic 0W20 will have a higher NOACK value which in a GDI engine you would want to use the lower Noack 5W20 synthetic oil if you had a choice ? ... *Are OEM's of GDI engines (Mazda again) trying to ensure that with a 0W20 you will have to use full synthetic OR a synthetic blend at a minimum versus stating a 5W20 is also acceptable out of concern you will use a conventional 5W20 instead of a lower NOACK oil in a GDI engine ?
Also , if I have a GDI engine (Mazda) , I don't live in a very cold environment - then why wouldn't I want to use a 5W20 synthetic in my GDI engine and enjoy a lower NOACK that would aid in keeping intake valves cleaner than 0W20 with the higher NOACK ? Other than cold start protection I can't see a reason to use a 0W20 synthetic versus a 5W20 synthetic oil ... Your thoughts and experiences ?

You have a lot of misconceptions.

NOACK has nothing to do with deposits. Reducing the NOACK is primarily for reducing the oil consumption. Why do you think if an oil evaporates faster, it would leave more deposits? In fact, it's the other way around. Base oils with lower NOACK/lower viscosity have lower aniline points, which means higher solvency and cleaning power.

Also, 0W-20 tends to have better base stocks than 5W-20, which also decreases deposit formation.

Therefore, 0W-20 cleans better than 5W-20 and leaves less deposits. However, the relative wear performance of 0W-20 vs. 5w-20 is more debatable.

It's also one reason why German Castrol and Mobil 1 European Formula are 0W-30 and 0W-40, respectively, instead of 5W-xx -- European engines require better cleaning.

See the section under solubility. Lower aniline point indicates higher solvency:

https://www.tri-iso.com/documents/exxonmobil_chemical_spectrasyn_plus_Brochure.pdf
 
Originally Posted By: Gokhan
...NOACK has nothing to do with deposits. Reducing the NOACK is primarily for reducing the oil consumption. Why do you think if an oil evaporates faster, it would leave more deposits? In fact, it's the other way around. Base oils with lower NOACK/lower viscosity have lower aniline points, which means higher solvency and cleaning power.

That's interesting. I would have thought that an oil with lower NOACK would have less oil vapor circulating through the PCV system, past the intake valves and into the combustion chamber. Thus, less deposits.
 
Lower Noack volatility is always better.



ASTM D5800 - 08 Standard Test Method for Evaporation Loss of Lubricating Oils by the Noack Method

http://www.pqiamerica.com/Testdescriptions/Noack.html
Quote:
Noack volatility determines the evaporative loss of engine oils. This test is important because the operating temperatures of an engine will typically drive off the lighter ends of a lubricant while in service. This effectively results in increasing the viscosity of the lubricant to a more viscous (thicker) level and, as a result, fuel economy goes down due to an increase in parasitic load.

The evaporation loss is of particular importance in engine lubrication. Where high temperatures occur, portions of an oil can evaporate. Evaporation may contribute to oil consumption in an engine and can lead to a change in the properties of an oil. Oils failing to meet the volatility limits will struggle in many oxidation tests including the sequence IIIG engine test which is a critical and sometimes formulation defining test. This test is impacted by many factors including the Noack volatility. Anti-oxidants can improve oxidation control but cannot prevent evaporation of the base stock leading to rapid oil thickening.



 
Originally Posted By: wemay
Oils failing to meet the volatility limits will struggle in many oxidation tests including the sequence IIIG engine test which is a critical and sometimes formulation defining test. This test is impacted by many factors including the Noack volatility. Anti-oxidants can improve oxidation control but cannot prevent evaporation of the base stock leading to rapid oil thickening.

Hmm, very, very false and misleading information by ExxonMobil PQIA there. (I later realized that it was PQIA's statement. ExxonMobil's statement on their advertorial is correct.)

Possibly more oil top-offs with higher NOACK, sure. However, oil oxidation has nothing to do with lower NOACK. Of course, a Group I or II oil will oxidize faster than a GTL or PAO oil and will also have a lot higher NOACK. But that's simply false correlation. It's comparing apples to oranges. What if they compared within the same base-stock slate, such as GTL to GTL or PAO to PAO? Would a lighter PAO oxidize faster than a heavier PAO? No! Sequence IIIG doesn't test for NOACK nor it's negatively affected by lower NOACK for a given base-stock slate.

Originally Posted By: turnbowm
That's interesting. I would have thought that an oil with lower NOACK would have less oil vapor circulating through the PCV system, past the intake valves and into the combustion chamber. Thus, less deposits.

I don't think evaporated oil would condense on hot surfaces. It would simply burn off in the combustion -- the whole idea behind PCV. My intake manifold was clean as new when I examined it, despite the PCV. Also, most oil you get on the intake valves and cylinders comes from transport, not evaporation.
 
It will make absolutely no difference if you use a 0w-20, 5w-20, or 5w-30 for the 5000 mi OCI typical for GDI engines. Just use a high quality major brand. The 0w-20 variants tend to have higher higher quality base stock than the others, but it isn't worth paying extra for them.
 
My understanding is OCI has no bearing on evaporative loss. Oil temps determine this.
 
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