Oil Viscosity / How Fast Is Fast?
 

I’ve dramatically changed my driving lately and I’m wondering if I should change the type of oil / oil viscosity I’m using.

The manual says “an oil with a higher viscosity may be better suited if the vehicle is operated at high speeds...”

What constitutes “high speeds?”

Up until this point I’ve used the Toyota 0W-20

I’m driving 700 miles a week at 70-80 mph. This mileage will continue for the foreseeable future. Should I look at a 0W-30 or 0w-40 oil?

2018 ORP
50,000 miles

https://uploads.tapatalk-cdn.com/201...e5a23c2489.jpg


Sent from my iPhone using Tapatalk

When it comes to the engine, higher speeds to me means higher RPMs.

Perhaps you re-geared your truck, and hit a max speed of 75 MPH at 4000 PRM, maybe then I would start to concern myself. Or if you have a dramatically increase standard load, as in you tow heavy things regularly, at lower gears, which also increases RPM.

I would just follow the standard weights based on what you are saying here. Its rare that most of us here would be operating outside of a condition of the service manual.

100% correct! Way too many folks overthink motor oil. The engineers at Toyota designed the engine to handle a huge range of speed and loads. Remember they are the ones who have to warranty the engine if something happens to let go inside. Toyota says 0W-20, that's what i'm using, especially as long as I am in warranty.
Given modern CNC machining tolerances, just how close are the clearances between the crank and the bearings? just how thick (heavier) can you go before the oil pump cant push the oil to the bearings fast enough? I dont know...do you? This is not a subject I want to argue with the Toyota folks over is there is a warranty issue....

FWIW, Both Mercedes we have owned ran 0W-40 Mobil 1. One is a 330 HP 8000 RPM 3.5 V6. The other was a 5.5l twin turbo V12 producing 525 hp/630ft lb. Both engines run as smooth as a turbine engine..never an issue with oil.

Personaly, I'm not worried about the "0w-20" rating, and cant think of a situation where I would need to consider a heavier oil.

Yep. You're fine on stock 0W20 viscosity. I run all highway and at 135k now, it runs the same as when I got it with 50k.

I ran 5W-30 once since I had a brain fart and bought what I would buy for the wife's vehicle by mistake, so I just used it. Dead of winter in the NE and no ill effects there either BTW. You could do it, I don't see why you would need to though.

Wait... you're saying that devoting page after page after page to arguing the relative merits of one brand of 0W-20 synthetic oil to another equivalently-rated brand is... overthinking???

Ummm...Yeah!:lol:

Look at it this way. The manufacturer decides what weight and spec oil is to be used in the engine they produced. Not me. I am not a petroleum engineer or a synthetic oil chemist. The manufacturer has to pony up for repairs if the engine grenades while taking the kids to school. They spec the oil accordingly. I am perfectly OK with that reasoning. Have been for more than 40 years and dozens of cars and motorcycles. NEVER have had an oil related engine issue.

That said, the problem occurs when someone thinks they are smarter than the engineering team that designed the engine and it's lubrication system. They try the latest and greatest oil supplement, or they cheap out and buy dino oil (can you even get that anymore?) Does dino oil meet the SN spec Toyota recommends? Or they go and get a $9.95 oil change at the corner lube shop, trusting that the shop will put in the correct spec and weight oil.

(We can sidebar on why my daughter driver a 4Runner now instead of her Equinox with the ruined engine) OIL SPECS MATTER...not the manufacturer so much.
Use the spec oil the manufacturer recommends in the range of weights they recommend and you will be just fine.

As others are saying, oil is WAY over-thought among vehicle owners. The very LAST failure you'll ever have is oil-related. And also, like others are saying, the manufacturer came up with their specs and recommendations after much more research than any armchair oil guy will ever invest. In my many years of driving, I only know of ONE oil-related engine failure. That's when my brother allowed his 1985 Corolla GTS run out of the stuff. I'm guessing nobody on this forum has ever experienced excessive wear or engine failure on an engine that had plenty of oil, regular oil changes, and oil that was even somewhat close to spec.

0W20 developed for fuel economy reasons and the engine will obviously perform well with it under most circumstances. But, if you live in desert regions and take your rig out there frequently and put the hammer down for extended periods, or, as has been stated, you are turning high revs for extended periods ( autobahn type driving), then go to a 0W30, 5W30. The high oil temps generated in severe duty may allow bearing, cam, etc. damage.

0/20 is a MPG concession for EPA.....this motor is allowed up to 10/30 in other, less regulated markets. 75/80 on the Freeway is not severe duty so just run the 0/20 and get better mpg.