Viscosity: Engine protection Vs. enhanced mileage

[ckinch1]

Use 5w-30 in my wife's 2013 sienna with 2gr-fe engine, she's at 185,000 miles. They changed the oil for CAFE rating but not the engine. Not sure what engine is in that 2022 Lexus, but I'll say confidently you can use 5w-30 with no problems.

 

[Carlostrece]

It's not that I (or anyone else) thought you couldn't understand the Stribeck curve. It's a simple concept that just sounds complicated. It's that we thought you just wanted some brief, easy, practical, relevant, helpful advice.

I now see that you enjoy the minutia and weeds. I think you're over thinking this topic, but that is fun when you're into that. You're going to fit in well at BITOG. Enjoy.

I doubt that getting harder on the throttle at take off would be easier on your vehicle, but I'll leave that discussion to others. I'm impressed by your fuel economy.

 

[Sunshine Guy]

(clip)...we thought you just wanted some brief, easy, practical, relevant, helpful advice.

(clip)...I think you're over thinking this topic, (clip)

All replies, brief and otherwise, have been relevant, helpful, and appreciated.

I have to agree I'm probably over-thinking this topic (I'm told I excel at this).

I did some google searching and found multiple references showing that both 0w-20 AND 5w-30 are recommended BY TOYOTA for my 2GR-FKS engine in numerous countries other than the CAFE-addled USA. While that may not settle which oil is "best" for my particular driving conditions, it gives me confidence to move to the PUP 5w-30 without trepidation.

 

[Carlostrece]

I did some google searching and found multiple references showing that both 0w-20 AND 5w-30 are recommended BY TOYOTA for my 2GR-FKS engine in numerous countries other than the CAFE-addled USA. While that may not settle which oil is "best" for my particular driving conditions, it gives me confidence to move to the PUP 5w-30 without trepidation.

For sure you can use 5w30 with no worries. In Florida it'll be an improvement, IMO. Besides, PUP 5w30 is relatively thin for 5w30. PUP 5w30 is only slightly thicker than most other brands 5w20.

I think PUP 5w30 is your best option because it's good oil (other than being thin per grade) and it's the chemistry that's already in your engine. So it wouldn't be a change in chemistry.

If you change brands of oil, that's a change in additive chemistry. According to Lake Speed Jr, changing additive chemistry sometimes causes increased wear because of competing additive packages. That would stop being an issue at the 2nd oil change using the new type oil. It's not a big deal, but if you're slitting hairs, you can avoid extra wear by staying with same brand/model of oil (even if you go up a grade).

 

[trd1zz]

One of those several conclusions is that you shouldn’t stray from your manufacturer’s recommended oil viscosity unless you have a specific reason to do so. After thinking about it, my reason would be this: I drive my 3.5L Lexus very conservatively, very light throttle 99% of the time.

If you always drive like an old lady and never get the revs up you are going to have carbon issues down the line regardless of using 0w20 or 5w30. Toyota D4S on the -FKS may help prevent or delay some of this but still it doesn't hurt anything but your fuel economy to drive it hard once a week. (italian tuneup). The 2GR likes to rev.

 

[Carlostrece]

If you always drive like an old lady and never get the revs up you are going to have carbon issues down the line regardless of using 0w20 or 5w30. Toyota D4S on the -FKS may help prevent or delay some of this but still it doesn't hurt anything but your fuel economy to drive it hard once a week. (italian tuneup). The 2GR likes to rev.

Good point. I don't know if, or how much, revving is needed, but one good 30+ min high speed highway drive per month is defineately helpful for keeping engine and oil clean. You might also be correct about the occasional (at least monthly) revving. I make sure my car does those things once a month.

 

[Revving2Redline]

The official weighting in the EPA test cycle is 55% city, so not hugely biased towards city driving.

But, based on the description of the elements of the test cycle, major portions of the city cycle are with cold oil. So the OEMs are often targeting the viscosity at oil temps significantly less than full hot-day-equilibrium.

I'm certain that the exact nature of this test cycle figured *heavily* in the final selection of oil viscosity grade and that OEMs aren't too concerns whether the engine wears out in 150k miles or 400k miles. They know that the real world variability is so large between the best and worst owners and duty cycles that it's almost impossible to ascribe engine life (or the lack of it) to a particular oil viscosity grade being used or not used.

These debates on viscosity only matter really in the rarefied air of BITOG. The OEMs are just running hurdle tests and if it passes, it passes. Most engines can tolerate a VERY large range of viscosity-- as they must, since oil viscosity is so extremely variable with temperature ranges that are normal for every engine.

Lots of long-lasting engines have been run on thin oils as well as thick oils. The famous example of the man who put a million miles on each of two different Tundras did so using TGMO 0w-20 on 10k change intervals suggests that there are conditions under which a "thin" oil is perfectly sufficient.

Engines wear out with thicker oils and thinner oils alike, just for different reasons.

Since engines vary so wildly in factors like how they heat oil and how much they shear it in different areas, what's "thin" for one engine might not be very thin at all for another. Film loads are not the same for all engines.

It's possible a 0w-8 is perfectly acceptable in actual running viscosity if the engine is 1) engineered with very small clearances in bearings, 2) runs a lower oil temperature of 70C or so, and 3) is designed with low film loads. Low film loads mean things like larger bearing area relative to load. Or lower cylinder pressure for a given piston ring diameter-- that kind of thing.

Note the very thin 0w-8 oils are only used in hybrids with very low average oil temperatures and frequent start/stop where speed of oil pressure arrival is perhaps more important than a point or two of viscosity.

8w would need to come from Amsoil, High Performance Lubricants or Redline for me to even be able to sleep at night. I would at least want an oil cooler and a bigger oil filter to get that fluid capacity up.

 

[DirectRejection]

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Welcome to BITOG, new members.

 

[TiGeo]

Welcome to BITOG, new members.

So let it be written...so let it be done...

 

[ripcord]

The cold viscosity of 0w-20 and 5w-20 are actually very very close. Just compare the SDS’s.

The statement “If 5w-20 is used, it must be changed to 0w-20 at next oil change” is objectively complete nonsense. It all has to do with CAFE, and Toyota has to recommend 0w-20 at all times for obvious reasons. Only time you might benefit from 0w-20 over 5w-20 is if you happen to live in Antarctica or somewhere that gets extremely cold.

If I were you, I would just use regular 0w-30 or 5w-30 and you’ll actually be able to get more miles/time out of the oil by having some fuel dilution and shearing buffer.

If you’re worried about warranty, do not use Mobil 1 ESPx2 0w20. That oil is green, and it’s super obvious that it’s an oil not recommended by Toyota just by the color of it. If anything happens and you gotta go to the dealership, they will see that green oil, and it will raise questions.

I think the main reason Toyota prefers 0w-20 may be because it seems to almost always come as a full synthetic, whereas 5w-20 oils can come as semi-synthetic blends. It's added insurance for their 10k oil change intervals, I guess.