Waffles17

I believe the correct oil for this car is Synthetic 5w30

I have a couple of questions.

I have quite a bit of Motul xcess 5w40 oil, can I safely use it instead of tm5w30 in summer?

As far as witer, I usually put Mobil 1 0w40 on my other cars (turbo and supercharged).

What's the recommended oil for the is350 in Canadian winters, and would it be safe to use the 0w40?

thanks all

NickCaesar

I live in Canada. My 2015 350 AWD calls for 0w-20 and that’s what I run year round.

Waffles17

Well 5w40 is actually better in summer than 5w30. Specially on hot days and the car is driven hard. Its however thicker.i just need confirmation if someone ran 5w40 and experienced any issues

In winter, am gonna go 0w30 or ow40, also need confirmation if it's ok.

NickCaesar

Why don’t you want to use the 0w-20 Lexus recommends for Canada?

Sasnuke

Correction to the above...the recommended oil for the IS in this region is 0W20.
It is true in other parts of the world where it is hotter, 5W30 is the recommended oil.

While we have had a nice hot summer this year, this is far from other regions where they are hotter, and consistently hotter year round.

I use 0W20 year round without issue.

Waffles17

Oh they recommended 0w20 or 0w30 for winter??

NickCaesar

Its different region to region, in Canada, Lexus says 0w-20 year round...

In not an engineer, unlike some ppl on here that mention they are every post, but someone like Sasnuke can probably tell you if running a slightly thicker oil in Canada, just for hot months (not winter) will have any benefits/disadvantages... my understanding is if you went slightly thicker just for summer you’d likely be fine. Personally I just run the recommended 0w-20 year round, cars at 90,000km no problems.

Waffles17

Looks like lexus designed the engine for XXw20 or 30

So 0w30, 0w20, 5w30 are all perfectly fine.

Worst case I can sell the Motul 5w40 I have (since its brand new) and get the right oil for the car.

NickCaesar

Where in Canada are u? Winters in B.C are different from Ontario. Warm temps probably won’t matter going up a level of viscosity, but on a -40 Celsius winter morning cold start in Ontario I definitely don’t want a thicker oil. Just my 2 cents.

V350

The whole advantage of synthetic oils is they have different properties at different temperatures. 0W-20 oil operates like a 0 oil in winter (W stands for that), and a 20 weight in op temps. Maybe if you are tracking the car hard, you go with 5W-30. But If you are DD the car, with some spirited drives, these cars aren't known to overheat (either the 200/300 or 350).

Sasnuke

OP is from Toronto.

Just my take on the oil...in the manual (going from memory) it states you can use 5W30 if 0W20 is not available. But it advises to switch back to 0W20 on the following oil change is you had to put 5W30 in.
Looking at the temp range for different weight oils, and taking into account that 0W20 is synthetic, given the climate we have in Central Ontario and that this is not a forced induction motor, the 0W20 pretty much is a perfect fit.
Given the temp swing that occurs plus the max temps you will see, there wouldn't be a ton of benefit to switching to 5W30 in the summer.
There might be that odd day here and there the temp may be above the norm, but it's not like we're living in Arizona either.
Realistically a big part of the reason manufacturers use the oil they use is to do with fuel mileage...thinner the oil better the mileage.
I think currently in some places you can get 0W8...or soon you can get it.

I haven't seen Lexus recommend 0W30, but then again I haven't checked every region on the planet the IS is sold...it's possible they recommend it somewhere.
It would seem kinda odd though as 0W20 would perform better in the cold, so I'm not sure how the 0W30 would factor in...maybe a climate like central US maybe...it would seem odd though.

Waffles17

Am surprised they recommend 0w20 all year long.

Looks like these engines like thin oil.

On my german cars I put 5w40 in summer, 0w40 in winter.

Sasnuke

Is that what the manufacturer recommends? Or is that your own personal practice?

I ask because with manufacturers trying to squeeze out as much mileage as possible between service stops, this would mean you would be committed to 2 oil changes a year. As many manufacturers are moving to a maintenance reminder system that calculates when the vehicles need an oil change it lets the driver know, its not based on an arbitrary time or mileage, therefore you could drive an entire year before the vehicle says its time for maintenance.

Toyota has always used one oil year round in their vehicles, so having a seasonal oil recommendation may be a very new concept to most. When I started driving Toyotas they used 10W30...i think i might be dating myself lol!!! Of course I was at the tail end of the 10W30 era.

Waffles17

They recommend 5w40 all year. I use 0w40 because temps get to -40 in winter.

0w20 is Good for winter, but damn is it thin for summer. Maybe its the fact that the is300/350 is a NA engine, so it does not get as much heat as a supercharger or turbo engine. Or it could be the internal design of the engine.

Sasnuke

Likely you're correct that the forced induction combined with internal engine clearances is why they recommend 5W40.
If you're in Toronto I'm not sure how often it gets below -35, much as less -40. Im north of Hwy 7 in Richmond Hill, so guaranteed its colder up here, and that's still nothing when you look at Sudbury in January. For them -40 is flip flop weather lol!!

Have you noticed an increase in oil consumption when you run the 0W40?