Chosen Oil Viscosity...?

show a single study or example of thinner viscosity increasing engine life and reducing wear....

 

Show a single study that shows a higher viscosity does.

 

watch every wear test that '' the oil geek'' and '' project farm'' has done comparing the exact same oils but different thicknesses. its a physics fact. the downside is thicker oils hurt gas mileage and also REDUCE HORSEPOWER. double wammy! plus thicker oils have more trouble in colder weather. so you sacrifice power, fuel economy, and cold starts in favor of longevity when going to thicker oils

 

If you rely on the Oil Geek and Project Farm to obtain scientific information on tribology, which is a very complicated subject, good luck.

 

Oil drain back over time on a Prime may be different with thin oil. The rough starts after longer periods of non use are not benefits to less wear. It’s like starting after an oil change. Not sure if Toyota tested such things. I still use what cap says. I think it must drain out through the crankshaft bearings back to the pan.
On my Ford I could hold the gas to the floor and the engine will not start, so can get oil pressure up into the engine, then start with no rough start. They sort of did away with that on newer cars I think.

 

Every oil is extremely thick at cold start—no matter what the viscosity is.

 

Are you saying 0w-16 drains out from bearings the same as a 5w-30 grade? Drain out starts from hot. You have your oil changed at a shop. I don’t, and can visually and noticeably see the 0w-16 pours thinner, and drains out thinner. Besides I wasn’t writing about the oil at cold start viscosity, but the oil drains out over long periods of non use of the engine. It does.

 

These are the typical viscosities at 100 ℃ and −10 ℃, respectively:

SAE 5W-30: 9.8 cSt, 880 cSt
SAE 0W-16: 7.1 cSt, 520 cSt

Operational viscosity | Widman International SRL

What I was saying was that, in a cold engine, you are looking at a viscosity many orders of magnitude higher (tens, hundreds, thousands, tens of thousands times higher depending on the temperature) than at the normal operating temperature.

 

Does the difference lead to a difference in the amount of oil left up in the parts of the engine? That's what he is talking about.

 

When I got this car used, the new car dealer changed the oil and filter, not Toyota. I heard no sounds. After I changed it to Toyota 0w-16 oil and N1 filter, sounds. Put Fram Ultra on, stayed the same it seems. My guess is dripping down through the main bearings. May not be that. I have a couple more changes of 0w-16, otherwise I would try 5w-20 as an experiment.
My first new Prime had the sounds from new, even more than this one. It’s just a little start up rattle. If it sits for like a week or less, not really anything.
I may go 5-20 anyway, seeing the temp chart. I like you have no worries about being out of the ranges.

 

It does not, and I have owned two Prius Primes since 2019 and always used TGMO 0W-16 and never experienced the issue he is talking about.

 

Well I am doing my experiment anyway. I know what the conditions are. One month no use of engine or longer. A very quiet place to start the engine cold at rest. No cars driving by, no ambient noise.
I don’t create the sound. My car has 22k miles. I am not loyal enough to my vehicle to not hear what I hear.

 

I feel for those buying the 2025 Camry's.....they only take 0W-08....I haven't seen a SINGLE quart of the stuff in the stores here and heard it's only sold by Mobile One and Toyota brands.
I just searched and, now Walmart.com does have it but only on-line, $27.97 for 5-quarts so that's good....right on time!
People who play around with various viscosities on their vehicles scares me.....you're playing with fire....only use what's on the oil cap, period.
When I worked in the heart of Alaska (Fairbanks and Delta Junction) where it can get down to -70, they don't recommend changing the viscosity but do only use full-synthetic oils in everything. (And put electric warmers on everything, including the 12-volt batteries.)

 

wonder how a new prius would perform with 0w-8 versus the 16? since its the same engine as the newer toyotas. could be beneficial. maybe with the 2025 prius toyota will start recommending the 8

 

SAE 0W-8 JASO GLV-1 is probably safe to use in Gen 5 Prius. It should result in about a 1% improvement in fuel economy.

https://www.walmart.com/ip/Mobil-1-Advanced-Fuel-Economy-Full-Synthetic-Motor-Oil-0W-8-5-Quart/5040310278

 

This whole discussion has ignored one important issue that goes beyond just engine lubrication: the oil plays an essential and important part of controlling timing in these engines, plus cooling other components (at least from what I’ve learned). I wouldn’t change the viscosity unless I was certain I knew how it effects the other components.

 

In his defence, oil geek AKA Lake Speed Jr. is a tribologist..

 

How would anyone be able to measure this?
Who keeps MPG records that even stay within ± 3%?
Is that the only reason to change to an 'off label' viscosity?
All this talk about 'drain back' and 'engine rattle at startup', is a subjective opinion.

 

"Tribologist!" That's funny....I have a business card from my friend at my Toyota Dealer who sells cars and his job title is listed as "Automologist"

I don't remember that being on the list at Job Fair in High School!!!

 

Tribology - Wikipedia