Towing grade engine oil
Instructor
Joined: Nov 2015
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From: Atlanta, Georgia
Here is what people miss. While thiner oil “works” and people get higher milages on thinner, thicker oil provides more protection when its needed (such as towing or driving at high speeds). Its like extra insurance that you may not need depending on your driving, but good to have just in case. And btw, engine cleanliness has nothing to do with viscosity, its about how often you change oil and quality of oil.
The only reason 2GR-FE was moved to thinner oil is to meet CAFE standards, they made ZERO design changes, let it sink in ….
The only reason 2GR-FE was moved to thinner oil is to meet CAFE standards, they made ZERO design changes, let it sink in ….
Everyone thinks they know more than the company that designed the engine in these forums.
If Toyota decided to use 0W-20 engine in the engine is was for a good reason which did not affect the engine reliability in a negative way. In fact many of the early 3.5 V6 engines that ran 5W-30 oil had issues more so than the later models that began using 0W-20 oil.
The 3.5 V6 did receive minor updates and improvements over the years since its production in 2007 with 0W-20 oil being one of the improvements.
Thicker viscosity oil is not always better for an engine. That is a old myth.
Last edited by carguy75; Feb 24, 2026 at 07:28 PM.
Instructor
Joined: Dec 2011
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From: NJ
No offense but you are not an Toyota engine engineer I bet. Therefore, you really do not know exactly what oil viscosity is best for the engine.
Everyone thinks they know more than the company that designed the engine in these forums.
If Toyota decided to use 0W-20 engine in the engine is was for a good reason which did not affect the engine reliability in a negative way. In fact many of the early 3.5 V6 engines that ran 5W-30 oil had issues more so than the later models that began using 0W-20 oil.
The 3.5 V6 did receive minor updates and improvements over the years since its production in 2007 with 0W-20 oil being one of the improvements.
Thicker viscosity oil is not always better for an engine. That is aold myth.
Everyone thinks they know more than the company that designed the engine in these forums.
If Toyota decided to use 0W-20 engine in the engine is was for a good reason which did not affect the engine reliability in a negative way. In fact many of the early 3.5 V6 engines that ran 5W-30 oil had issues more so than the later models that began using 0W-20 oil.
The 3.5 V6 did receive minor updates and improvements over the years since its production in 2007 with 0W-20 oil being one of the improvements.
Thicker viscosity oil is not always better for an engine. That is aold myth.
Instructor
Joined: Nov 2015
Posts: 1,064
Likes: 362
From: Atlanta, Georgia
All 3.5 engines was filled with 5W-30 oil back then before Toyota switched over to 0W-20 oil.
Toyota did not start using 0W-20 oil in the 3.5 engine until about 2010.
This video sums it up that 0W-20 is a good quality oil that is in line with the older 5W-30 oil but with better start-up protection. However, like anything in life it never a black and white situation. Brand of oil and how the engine is used are all factors on how well an 0W-20 oil will protect an engine. 5W-30 may be the better option for a RX350 towing a trailer.
Last edited by carguy75; Feb 26, 2026 at 12:14 AM.
Thread Starter
Pit Crew
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From: AB
Thanks for input on yet another thick/thin motor oil thread, we use Mobil 1 ESP 5w30 on other Toyota and Scion family cars and a Nissan Titan truck which is on it's way to 300k miles; like the C30 Porsche approval and can always get this oil at good price at local stores. I'll likely use Mobil 1 ESP 5w30 for towing with RX, HTHS of this diesel oil is actually into 40 grade territory.
https://www.mobil.com/en/lubricants/...il-1-esp-5w-30
https://www.mobil.com/en/lubricants/...il-1-esp-5w-30
Last edited by 6runner; Feb 25, 2026 at 01:20 AM.
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From: NJ
I never provided owner manual for rx350. I am not going to waste my time searching for one, there will be something else you dont like…. Lake Speed Jr did mention that thicker oil provides more protection, all this video is saying that 0w-20 might be adequate, but not better, lets not confuse two things
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Joined: Nov 2025
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From: Palm Beach, FL
My 2015 RX350 has over 190k miles and I only use high quality Valvoline 0W-20 full synthetic high mileage oil. The engine does not burn oil and the engine runs like brand new.
Furthermore, when I pulled the front valve cover to replace the valve cover gasket and spark plug seals the engine was brand new looking on the inside with no visual sign of excessive wear on the camshaft lobes. 0W-20 oil works just fine with proper 5k mile oil change intervals. No need for any thicker viscosity oil in the 3.5 V6 engine.
Here is what my engine looked like under the valve cover with 5k miles oil changes and 0W-20 weight oil use with over 190k miles. No varnish and basically bare aluminum. Almost brand new.
Furthermore, when I pulled the front valve cover to replace the valve cover gasket and spark plug seals the engine was brand new looking on the inside with no visual sign of excessive wear on the camshaft lobes. 0W-20 oil works just fine with proper 5k mile oil change intervals. No need for any thicker viscosity oil in the 3.5 V6 engine.
Here is what my engine looked like under the valve cover with 5k miles oil changes and 0W-20 weight oil use with over 190k miles. No varnish and basically bare aluminum. Almost brand new.
Did you use an endoscope to examine the condition of the cylinder walls?
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From: Palm Beach, FL
And to all of those people that say “manufacture knows best”, none of the counter arguments make them change their mind. It was mentioned several times that 2GR-FE used in Lexus ES350 2012 and older and Toyota Avalon of same years had 5w-30 in its manual.
The internal parts of 2GR-FE been compared between 0w-20 and 5w-30, and they have not changed to accommodate thinner oil, so please…
There are also foreign countries that sell same car have 5w-30. Some toyota manuals even suggest that thicker viscosity is more suitable when vehicle is operated at higher speeds or loads.
The thiner viscosity lets car makers get better MPG, so they can meet their CAFE requirements, thats all there is to it. The engines are designed to operate at viscosity range, this is necessary when engine started cold and oil viscosity is thicker.
Cafe requires them to put only one viscosity in the manual that gives best MPG. They are legally not allowed to put multiple viscosities. Thank CAFE and government
The internal parts of 2GR-FE been compared between 0w-20 and 5w-30, and they have not changed to accommodate thinner oil, so please…
There are also foreign countries that sell same car have 5w-30. Some toyota manuals even suggest that thicker viscosity is more suitable when vehicle is operated at higher speeds or loads.
The thiner viscosity lets car makers get better MPG, so they can meet their CAFE requirements, thats all there is to it. The engines are designed to operate at viscosity range, this is necessary when engine started cold and oil viscosity is thicker.
Cafe requires them to put only one viscosity in the manual that gives best MPG. They are legally not allowed to put multiple viscosities. Thank CAFE and government
It's strange why they don't drink breast milk their entire lives; it's the" manufacturer's" recommendation...
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Joined: Nov 2025
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From: Palm Beach, FL
If you plan to dispose of your car after the warranty period expires, you can follow the advice and recommendations of the manufacturer or authorized dealer. If you plan to drive it twice as long, it's worth considering and listening to the advice of more experienced owners.
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From: Palm Beach, FL
p.s. What they don't know is that in different countries, official Toyota dealers often use different brands of oil in the original barrel (in Japan it's Idemitsu, in Europe it's Castrol, in the USA it's Mobil 1 - other brands may be used, I wrote this as an example).
Last edited by Alex1989; Feb 25, 2026 at 05:59 AM.
Driver School Candidate
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that mobil 1 esp x4 is a killer choice because it handles the high heat of towing without thinning out too much like a standard oil might. since it meets those tough european specs you know it has the shear stability to protect your bearings under load all summer long. just make sure your vehicle is compatible with a 40 weight and you should be good to go for the long haul.
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Joined: Nov 2015
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From: Atlanta, Georgia
Not all Toyota engines are that clean or in good health with nearly 200k miles just because they are Toyota engines as a rule. My engine looks and operate that good due to using good quality 0W-20 oil and a 5k miles oil change interval.
However, I am sure that 5W-30 oil would work just fine as well.
My point is that 0W-20 oil is a good oil for the 3.5 V6 engine with added benefit of better start-up protection due to its thinner viscosity that gets to the engine parts quicker.
To bring this topic back to the original discussion, 5W-30 would probably be the better oil choice for an RX350 that tows an trailer often as opposed to 0W-40 that the OP was thinking about using.
Last edited by carguy75; Feb 25, 2026 at 07:19 PM.
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Joined: Nov 2015
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From: Atlanta, Georgia
I never provided owner manual for rx350. I am not going to waste my time searching for one, there will be something else you dont like…. Lake Speed Jr did mention that thicker oil provides more protection, all this video is saying that 0w-20 might be adequate, but not better, lets not confuse two things
Pros and cons like with anything.
However, 5W-30 does seem like a better choice for 3.5 engines that will be used in hotter climates or used for towing or racing like in a Lotus.
Last edited by carguy75; Feb 25, 2026 at 07:18 PM.
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From: NJ
If you are worried, for colder climate, you can use 0w-30 which has exactly the same startup/cold viscosity as 0w-20. But if you are in Florida, 5w-30 will also be fine.
