5w-30 too thick for modern cars?

[Number_35]

Suggest watching these videos if you want to understand viscosity in auto engines and the effects of changing it. The second video is recommended by Jason in the first video. The third video is a very well done AI generated. If not for a few mispronunciations, it'd be tough to know it was't a human reading a script. Good info on ACEA standards vs EPA standards.

Thanks for posting these - I watched Jason's (EE's) video (the first one), and found it very informative.

He mentions the special additive in the Mobil 1 0W-8 which provides adequate film strength even when the oil's viscosity is very low.

Some of us BITOG types would be pleased to see a 0W-30 oil with the same special additive.

As well, I'd heard that the Toyota engines for which the very thin (0W-16 and 0W-8) oils are recommended are built with lots of bearing surface area (so as to reduce the load per unit area). I don't know whether or not this is true.

 

[kschachn]

Thanks for posting these - I watched Jason's (EE's) video (the first one), and found it very informative.

He mentions the special additive in the Mobil 1 0W-8 which provides adequate film strength even when the oil's viscosity is very low.

Some of us BITOG types would be pleased to see a 0W-30 oil with the same special additive.

As well, I'd heard that the Toyota engines for which the very thin (0W-16 and 0W-8) oils are recommended are built with lots of bearing surface area (so as to reduce the load per unit area). I don't know whether or not this is true.

Meh. I would rather rely on intrinsic film thickness (not film strength BTW) to protect from wear. If I needed increased HT/HS than a -30 grade, I'd use a -40.

 

[Number_35]

Meh. I would rather rely on intrinsic film thickness (not film strength BTW) to protect from wear. If I needed increased HT/HS than a -30 grade, I'd use a -40.

Exactly - how would you know if the "special ingredient" actually worked?

UOA I suppose.

Per the EE video, the upside of using a thicker-than-specified oil outweighed any potential downside.

 

[JohnnyO]

My wife's 2023 Pacifica with the 3.6 calls for 0w-20. I was trying to find out if the European models called for 5w-30, I asked Grok and it seems that they do. I've been to Italy and they have Chrysler minivans there.
Here we don't have many days in winter when it's colder than 20*F.
My take is that 0w-20 won't kill your motor but wouldn't, and I don't, leave it in longer than 5000 miles.

 

[wemay]

Xw-20 vs Xw-30, much to do about nothing.

 

[cf42085]

My 2GR-FE has 5w-40 in the sump (0w-20 on the cap), just in time for winter.

I've been running chevron delo 15w40 in my 2007 avalon in Texas

 

[GSCJR]

I would too, but only in the summer.

 

[53' Stude]

My truck specs 10w-30 so why would 5w-30 be “too thick” ?

 

[Hohn]

Is 5w-30 too thick for modern cars?

So I recently purchased a 2019 Lexus is350.
It has a 2GR-FKS V6 in it.
Obviously the factory calls out for a 0w-20 oil.
Dealer had new 0w-20 in it, so after 5K miles, I swapped to 5w-30.
I figured running Mobil 1 Extended Performance 5w30 oil was fine since the early 2010s 2GR listed 5w-30 as the recommended oil.
I've run that 5w-30 EP oil in many cars that went above 300,000+ miles.

Within a day, the engine was running oddly.
The exhaust tone on mid throttle sounded weird. Kinda like a drone.
I thought it was leaking exhaust gaskets, but I changed them to no avail.

My brother had mentioned that some modern cam phasers don't like thicker oils. And since it's 50F out, I thought maybe the oil just wasn't flowing right.
So I used an OBD2 scanner to see what the cam angles were.
And sure enough, the cam timing was kind of erratic and laggy.

So I changed the oil to a Mobil 1 Extended Performance 0w20 and the issues are all gone.
No weird noises
Cam timing is consistent
And the car feels more responsive.

I always thought the difference between 0w-20 and 5W30 oil was minimal or non existent.
Apparently not

My IS250 had cam phaser rattle at startup shortly after I bought it (with 107k on it). There was a TSB.

Every OCI I used a 30 grade in the car and eventually the phaser rattle went away. When I sold the car (176k miles) it was running better than when I bought it.

The 4gr-FSE is not one of Toyota's best engines (GDI only) and this one in particular had a known carbon-up TSB that caused Lexus to swing several engine.

Mine was very reliable and had almost no carboning up top and barely any varnish at on the intake manifold. That, with no catch can added.

 

[Hohn]

I don't have a way to record OBD2 data history with the cheap reader I use
Maybe the $2,000+ code reders can do that.
But a guy that I work with used to be a master Toyota technician.
He said that thicker 10w-30 oils can sometimes interfere with VVT systems or variable cam lift stuff.
He said the earlier hybrids were very particular about using thinner oils.

I doubt the oils were left in too long.
Here's the oil test from the dealer 0w-20 and the Mobil 1 Extended Performance 5w30.
lowwr of equal to what Blackstone usually sees in 2GR

I just never realized 5w-30 would be worse than 0w-20

View attachment 312114

A lot of dealer techs really have no clue of the system dynamics, and they are regurgitating "training" they got from the factory. I place that training in quotes, because it's not about giving the technicians understanding, it's about conditioning them to toe the line for warranty purposes.

Fear the 5w-30 boogey man! Your engine will blow up!

It's garbage and it takes about oil 101 level knowledge to refute. Which is still beyond what most techs know.


Sad say, I'd say a good 80% of BITOGers know more about oil and engines than 90% of the people repairing them.

 

[53' Stude]

A lot of dealer techs really have no clue of the system dynamics, and they are regurgitating "training" they got from the factory. I place that training in quotes, because it's not about giving the technicians understanding, it's about conditioning them to toe the line for warranty purposes.

Fear the 5w-30 boogey man! Your engine will blow up!

It's garbage and it takes about oil 101 level knowledge to refute. Which is still beyond what most techs know.


Sad say, I'd say a good 80% of BITOGers know more about oil and engines than 90% of the people repairing them.

Solid points sir

 

[walterjay]

Gosh another thick vs thin discussion. It will never go away. Unless I lived in polar regions I would use 5-30.

May as well get my opinion in here too

 

[rumcapital23]

i run 0W-40 and 10W-30 in my 2GR engines still haven't blown up after all these years

 

[proffittmarke]

Is 5w-30 too thick for modern cars?

So I recently purchased a 2019 Lexus is350.
It has a 2GR-FKS V6 in it.
Obviously the factory calls out for a 0w-20 oil.
Dealer had new 0w-20 in it, so after 5K miles, I swapped to 5w-30.
I figured running Mobil 1 Extended Performance 5w30 oil was fine since the early 2010s 2GR listed 5w-30 as the recommended oil.
I've run that 5w-30 EP oil in many cars that went above 300,000+ miles.

Within a day, the engine was running oddly.
The exhaust tone on mid throttle sounded weird. Kinda like a drone.
I thought it was leaking exhaust gaskets, but I changed them to no avail.

My brother had mentioned that some modern cam phasers don't like thicker oils. And since it's 50F out, I thought maybe the oil just wasn't flowing right.
So I used an OBD2 scanner to see what the cam angles were.
And sure enough, the cam timing was kind of erratic and laggy.

So I changed the oil to a Mobil 1 Extended Performance 0w20 and the issues are all gone.
No weird noises
Cam timing is consistent
And the car feels more responsive.

I always thought the difference between 0w-20 and 5W30 oil was minimal or non existent.
Apparently not

People generally think that a particular vehicles same-size engine is the same yesterday, today, and forever. Truth is, constant changes are being introduced into production. The engineers are constantly working with vendors on engine parts, in response to warranty claims, weight, durability, cost reduction, efficiency. The testing laboratory is doing a host of various tests on parts falling under categories such as new, changed suppliers, different materials. On the qualifications paperwork, the weight of oil used for testing is listed. After engineering, testing, accounting and various management approvals are granted, the newly supplied part replaces the former part. On the same engine, there are many changes yearly.

Also, the engines are tested with the weight of oil(s) in your manual, nothing else. Note that I always saw big beige drums with Mobil 1 in big blue and red letters, regardless of the factory fill. So, if they have spec’s all the parts to be able to run 0W-20 or whatever, I feel that could be the best choice.

I’m aware of models that allow different weights in other countries. I’m also very aware of CAFE and CARB. So, one can wonder.

THINK OF THIS - Part changes are several time a year, every year. Let’s say a part change on a particular production date is made. The old part was tested years ago with 5W-30 (passed) and later with 0W-20 (passed). The new part goes into production with different critical characteristics AND it was only tested with 0W-20. It might be an issue.

 

[SC Maintenance]

THINK OF THIS - Part changes are several time a year, every year. Let’s say a part change on a particular production date is made. The old part was tested years ago with 5W-30 (passed) and later with 0W-20 (passed). The new part goes into production with different critical characteristics AND it was only tested with 0W-20. It might be an issue.

How does your theory account for the fact that xw-20 will have the same viscosity as xw-30 only at slightly different temperatures?

Oil temps fluctuate for all kinds of reasons, yet the engine must still run under all these conditions?

 

[proffittmarke]

Could you post the lab results for us?
My test above didn't show any difference in wear from 0w-20 to 5w-30.

How does your theory account for the fact that xw-20 will have the same viscosity as xw-30 only at slightly different temperatures?

Oil temps fluctuate for all kinds of reasons, yet the engine must still run under all these conditions?

How does your theory account for the fact that xw-20 will have the same viscosity as xw-30 only at slightly different temperatures?

Oil temps fluctuate for all kinds of reasons, yet the engine must still run under all these conditions?

Just followed testing protocols. The tests can cost megabucks and last a long time. There is no time or money to test various brands and weights of oils. I accidentally ordered 0W-30 instead of 0W-20 from Amsoil once and used it in my 5.3L L84 with no issue.

 

[GW.]

How does your theory account for the fact that xw-20 will have the same viscosity as xw-30 only at slightly different temperatures?

Oil temps fluctuate for all kinds of reasons, yet the engine must still run under all these conditions?

BINGO!!! 100% correct.

Oil temperature is by far the largest factor for viscosity. Not what’s printed on the bottle.

Oil viscosity is the second most misunderstood topic here, only second to winter rating….

 

[kschachn]

I can see how thicker oil could mess up a VVT solenoid.
Some have very small oil passages.
Seen a few 1.8L 1ZZ engines run like crap when bad maintenance clogges up solenoid passages.

View attachment 312123

Not sure what your claim is here.

 

[Sandra D]

No 5W-30 is not to thick for modern vehicles. Remember in some climates 0W-20 is more viscous than 5W-30. Like in Caribou, Maine from October to April….vs San Diego, California year round.

I wondered if this change would effect the engine. I have a 2025 Mit. Outlander and we felt like the engine did not sound good with the 0w-20, after switching to 5w-20, the engine sounds much better. And it runs the same.

 

[facility1]

I wondered if this change would effect the engine. I have a 2025 Mit. Outlander and we felt like the engine did not sound good with the 0w-20, after switching to w5-20, the engine sounds much better. And it runs the same.

try Pennzoil ultra platinum 5w-30 as it is a bit on the thinner side of a 5w-30, works great in my 2024 Subaru 2.0