Moisture

5w or 10w as opposed to 0w base weight has a clear purpose here. A turbocharger runs extremely hot (the exhaust section in excess of 1,000F under load) and even those that are water-jacketed still take enormous heat and shear-related stress in the center housing bearing. That bearing floats on an oil film and seals based on centrifugal force as actual contact at the RPMs involved would result in instantaneous destruction of the unit. A lighter base oil fails to be reasonably contained (e.g. excessive consumption due to bypass.) Hence which is why it's strongly not recommended especially for a turbo engine, which are particularly prone to potentially consuming oil. Since the oil gets quite broken down after going through the turbo, engine protection is inhibited.

I have went ahead and bought Motul 5W40 to use for my first oil change with this car. It is very rare for 0w20 to be specified for a turbo engine, even after stringent CAFE regulations here in North America.

- compromised engine and turbo protection
-poor seal between piston ring and cylinder wall due to thin oil = increased fuel dilution (oil shear) and oil consumption
-increased cylinder wall and piston ring wear
-increased valvetrain clatter
-Vehicles destined for everywhere else in the world come pre filled with 5w30 oil
-no where except for canada or united states is 0w20 "recommended:
-0W20 performed very poorly on a Japanese key deposit formation test
-the only thing protecting your engine oil from shearing is the additive package which must be formulated specifically to ensure the oil does not thin out. Most oils shear down at least one grade by the end of it's useful life cycle (eg. 5w40 becomes something like a 5w20 or 5w30 toward the end of its life)
- a 0w20 blend with an excellent additive package will more or less be okay, but how much thinner can the thinnest oil possibly get?
- I know somebody with an oil catch can on their Mazda CX5 (2.5L engine, naturally aspirated) who noted almost 500ml of blow-by after 7000 mile interval with 0w20. (they live in texas, hot weather) using 5w30 for the same duration, the catch can was completely empty. 0w20 causes blow by even if your engine is so well sealed that none of it is being physically consumed in between oil changes.

Moisture

Moisture

https://www.amsoil.com/newsstand/art...rgers-and-gdi/

• Reduced oil viscosity interferes with formation of a durable lubricating film, inviting wear. Combustion-zone parts are especially prone to wear, including the pistons, rings and liners. Reduced viscosity also negatively affects the oil’s ability to function as a hydraulic fluid, which is critical in engines with variable valve timing.

• Fuel can wash oil from the cylinder wall, causing higher rates of ring, piston and cylinder wear.

• Reduced effectiveness of detergency additives limits the oil’s ability to guard against deposits.

• Increased oil volatility results in higher oil consumption, requiring more frequent top-offs.

• Accelerated oxidation reduces the oil’s service life and requires more frequent oil changes.

Torii

just send your oil out to be tested if concerned https://www.blackstone-labs.com/abou...-oil-analysis/

they have made a new oil https://www.noln.net/articles/2277-t...y-on-ow-16-oil

DLUX

This looks to be from an IS350 manual?

chezgk

The uploaded page seems to be from an IS350's manual?

Based on the NX's manual, 0W-20 is one of the recommended oils for our tropical Philippine market. We get Gulf Coast Country (Middle East) units, so it's not some sort of mistake that this was one of the recommended viscosities. As most wear happens during cold starts, it makes more sense to prioritize room temperature flow characteristics (doesn't have to be winter temperatures) and oil delivery to the valves and other moving parts as soon as the engine starts running over protection at redline, not that there isn't any. I understand that the use of thinner oils, such as the 0W-16 that @Torii posted about, is made possible by the tighter production tolerances that modern manufacturing allows. Reputable manufacturers probably wouldn't have made the switch in the name of fuel economy if they didn't first test for reliability.

Well, this is all just my opinion.

coolsaber

use whatever you feel like. The only times you have to worry about is dealer warranty work on an engine failure....

Torii

I wouldnt say use whatever you want as back in the day I blew up a v6 w/ 20w-50 oil....

Torii

my previous is250 was made with 5w30 and then the world had a gas crisis and suddenly lexus said 0w20 was fine....it was for better gas mileage imo.

Moisture

Yes, it is from the is350 manual in UAE. Unlikely any of Toyota's other engines have tighter clearances than this.

If up to 20w50 is OK, that means, these engines are not "modern" with internal clearances, and that the internal clearances are not tight.

Unless you are using 20w50 and parking outside in a very cold winter, there is no problems whatsoever with cold start flow.

how do you know for sure 20w50 is what caused your engine to fail? there are so many potential causes for this, that its hard to say for certain.

Lexus was not the only brand to do this. It was mandated by CAFE, not due to anything else.

the 0.2MPG you gain from using 0w20 (mainly during a cold start) is easily and effectively offset by an increased buildup of carbon within your engine.

I think, the sweet spot is 5w50 in the summer, and 5w40 in the winter.

Danny200t

I know Audi recommends 5w40 on their turbo engines, i’ve been using 0w20 in the 200t changing it every 6-7000km. Would 5w40 be too thick? is it better to start using 5w20 or 5w30 instead?

Moisture

No, 5w40 isn't too thick.

Unless you park outside in the middle of a very cold winter, you can go even thicker if you want to. But I don't see much of a point going thicker than 5w50 in the summer unless you're planning to race.

coolsaber

Thats why you now follow the manual, which most folks do. Again if you dont like the manual or you know better or w/e do as you wish. The only time this becomes an issue is when folks want warranty, but the mfg denies it since you didnt follow the directions

Moisture

It's really not possible to prove much from pulling the oil sample from a blown motor unless you sent it in for analysis which the Dealer very likely won't do. They don't know what sort of oil you put inside your car without inspecting it. It's about using the right oil, to avoid these warranty claims from possibly happening in the first place.

coolsaber

Problem is, while this does not pertain to your current use case (your trying to find a better oil then the one spec`d) dealers love to dig their head into the sand when the opportunity arises. No tests required.