nazish1234

Hello everyone ,

I have a Lexus is350 2017 AWD f sport with 97k miles. The car is American spec and it’s imported to UAE. Now as per owners manual the recommended engine oil viscosity is 0w-20. Will it be okay if I use 5W-30 viscosity oil due to extreme hot temperature in Dubai and would that work well in the engine ? Any advice will be really appreciated.

LeX2K

You can't get 0W-30 or even 0W-40? If it was my car I'd run 5W-40 or the others I mentioned. 0W-20 is largely spec'd to maximize fuel economy.

nazish1234

Nope unfortunately due to hot climates here it’s very rare to find 0w-30 and 0w-40. Is it true that as modern engines need thin oil to run so using 5w-30 or 40 be too thick and damage the engine? Sorry I’m not very knowledgeable in the viscosities

BBQapple

Everyone seems to think they can outsmart the engineers who designed the car. If the oil is too thick it won’t flow properly. If it’s too thin it won’t provide protection.

LaZeR

Southern USA also gets pretty hot... 5W-30 should be an OK substitute as long as it's always (premium) Synthetic of course.

nazish1234

Thanks for the response , so just for my knowledge if I continue using 0w-20 even on a hot summer day would that somehow be bad for the engine or I will need to switch to a 5w-30 during hot summers?

Matroushi

This is a picture of my owner's manual if that helps. The majority of people here run 5W-30 or 5W-40.

LaZeR

I think it's fairly well known that different viscosities &/or blends should NOT be mixed - not even for top ups - ensure the old oil is always completely drained. On that note, it's OK to top up with the same viscosity.

arentz07

True, you'd need to change the oil out completely.

But yes, I'd say you should run 5w-30 if you think it's more suitable for your conditions. As long as the oil meets the API SN standard, it should be okay.

nazish1234

Draining the oil out completely as in a engine flush or just a normal service of emptying the old oil and replacing it with the new viscosity oil?

LaZeR

Your choice: 1) try to just always stick with SAME oil, 2) normal service will leave old remnants but should be OK, 3) flush is expensive.

GNS

My car came with 0W-20 as factory fill. I ran that for the break in period and for a couple of oil changes after that, then switched to a quality synthetic 5W-30. It's fine to switch over, you're not mixing large quantities of the old oil with the new fill, and it'll gradually be completely replaced by the 5W-30 after a couple more of those changes.

As for the viscosity, I won't put 0W-20 in my engine because I know that the 2GR-FSE was the same engine between the 2013 and 2014 models, but the owner manuals for both cars specify different viscosities (2013 5W-30, 2014 0W-20) right around the same time that fuel economy regulations changed. My own 2GR-FKS is an evolution of the 2GR-FSE, and still uses the same oil pump, same passages, etc.

I have also looked at the Australian owner manuals for my model (2019 AWD) and those seem to have more of an emphasis on proper maintenance than the North American manuals. For instance, they still have maintenance schedules and specify replacement of the transmission fluid at around 100k km, while NA manuals don't even say anything about that part.

Anyways, Australian manuals specify a much wider range of oils, I think even down to the 20W ones, and basically say 'use your judgement and choose the one that suits your temperature range'. Since it's not cold year round in Ontario Canada, and 5W-30 is still fine even when it's -30c, I can only conclude that the recommendation of 0W-20 is mostly for fuel economy and to streamline the oil recommendations for all of Canada including the regions that DO see lower than -30c in winter (ie. Calgary, Winnipeg, Nunavut, etc).

wongnee

I use 5W-30

ronkelley

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Where is it "well known" that you must use the same blend or viscosity? Mixing two different viscosities of the same brand, blend, and type of oil should just change the compounds only slightly. Here are some other opinions on mixing:

https://www.zigwheels.com/guide/oil-...ne-oils/19084/

https://www.jiffylube.com/resource-c...th-regular-oil

https://motorcities.com/can-you-mix-engine-oils/

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LeX2K

Tests have been done by mixing 5-6 different oils, there was nothing wrong with the oil it performed well. Not like the best out there but certainly didn't create some horrible brew that will ruin your engine.