ToYourGSE

I've taken a lot of interest in engine oil lately, weights, synthetic vs conventional, etc. and I always assumed the F required synthetic. After all, the 2UR-GSE a high performance engine with high compression, high redline, both port and direct injection, and was designed with track use in mind. Even if the engine specs themselves are fine with conventional in theory, I would think Lexus would recommend synthetic because of how this car was meant to be driven, or at least specifically recommend it for track use.

So it shocked me to learn, after reading the owner's manual, that synthetic oil is not mentioned once (at least for 2010), and that the recommended oil is Toyota Genuine 5W-30, which is decidedly not synthetic. By contrast, the manual for my 2003 Honda Pilot says you can use synthetic "if it meets the same requirements given for a conventional motor oil." This sounds like the factory fill was conventional, and that if you just brought it into the dealer for an oil change and didn't specify synthetic, you were getting conventional. Is this also the case for the GSF, RCF, and LC500?

My first thought when I found this out was that "I guess that explains the recommended 5000 mile oil change interval", which is overkill for a quality synthetic, but just right for a quality conventional.

Personally I always used Mobil 1, and changed it every 7500 miles. And it seems from my searches on this forum that well over 90% of you use a high quality full synthetic. But I am very curious to hear from people who use conventional or who have used it for a long time. How it performed and such

wktjr

Frankly, I can think of a reason why anyone would be using conventional. I've been using synthetic for at least 30 years.

MileHIFcar

There was a thread a while back that was discussing the OCI for this platform and a former owner of a RCF Daniel worked at a tribology lab and stated IIRC that he had inside information why Lexus engineers specd out conventional oil for this platform but said he couldn't reveal why that was the case for this motor? I always thought that was a perplexing comment that he never shed any light into why he said that so my guess is as good as yours🤷‍♂️.....but your right I use a high quality synthetic and have never considered using conventional in the 2UR-GSE

lobuxracer

iTrader: (2)

I'll never run Mobil 1 in a Toyota product again, but I've been running synthetic oils since 1989. Very happy with Renewable Lubricants performance based on used oil analysis and eliminating the random ticking noise my engine made from the left side cam chain tensioner with Mobil 1. when cold.

ToYourGSE

That sounds interesting. I very, very, much doubt conventional is better for the engine, but I wouldn't surprised if Toyota wanted to engineer the engine with tolerances and such that are designed for conventional, because ultimately that would be more reliable and durable. And to prevent some idiot who decided to put conventional oil in an engine that requires synthetic from ruining it. I'm kinda talking out of my a*s here, with a very limited knowledge of how engines work, but I would think if an engine is designed to run on conventional, it would have to be relatively simpler and more durable, and have less finicky tolerances than one specifically designed for conventional, yielding more reliability.

On a side note, the newer Toyota/Lexus I4's and V6's use 0W-20, which only comes in synthetic. I don't know if that means if those engines were designed for synthetic, or what would happen should someone decide to cheap out and put 5W-20 conventional in there (of which there is no advantage other than cost). Most if not all of Toyota/Lexus V8's use 5W-30 which can be readily found in conventional.

You were in pretty much every thread over the course of 12+ years regarding engine oil, and often posting detailed lab results which is greatly appreciated. I do remember you saying you stopped using Mobil 1 and settled on Renewable Lubricants. I am curious what oils you would recommend for this engine that are more easily acquired (i.e. Pennzoil, Valvoline, etc) ?

lobuxracer

iTrader: (2)

If I were still a MSgt in the Air Force making $40k a year, I'd be trying Quaker State Ultimate Durability 5w-30 for my IS F. Of course, I doubt I'd have this car at that income with 2 small children...I retired 21 year ago, so those limits no longer apply except for the small kids...

Gohanburne

What oil are you using now? I've seen Quaker State 5W30 and was about to go get some for my next oil change. Is there something "better"?

Yri

The main difference between conventional and synthetic oils is the additives. This basically allows for the synthetic oil to last longer, prevent more wear and other miscellaneous things. A car made to run on conventional oil will run just fine with synthetic, and a car made to run on synthetic oil is going to run just fine with conventional oil (albeit the viscosity is the same, and the change intervals are adapted to said conventional oil). I personally don't think running a synthetic car on conventional for a long time is a good idea, but it is totally possible (its not like your car is just gonna blow up if you change to conventional).

Also, I do recall Lobux saying that Castrol is garbage. For me, I used Amsoil full synthetic on my 2JZ, so far shes pretty dang quiet. I wonder what Lobux has to say about that, though.

flipside909

I used Eneos synthetic when I had my 2009 IS F since it was brand new. $10/quart but I thought it was well worth the protection.

ToYourGSE

For whatever reason, I was under the impression Quaker State was a bad oil. Guess not! Also, Lobux says he uses Renewable Lubricants


It’s not just additives. It’s refined more intensely and the molecules are more uniform in size leading to a better flow rate. Whereas conventional has more different size molecules.

Engineering explained has a good video about this:

lexicon72

I'll admit I am one of the 10%. I've been using conventional for 7+ years of ownership and 100k miles. I daily and track my F. Zero issues. I've debated going synthetic but haven't made the switch.

Yri

Yes, yes true, it is more refined, and that does aid to better flow, hence why it is called synthetic. Thank you for the correction.

ToYourGSE

If anything, that's a testament to how good these engines are. I'm happy to hear it

lobuxracer

iTrader: (2)

The truth is it doesn't matter if it's conventional or synthetic (and "highly refined" ignores the class of true synthetics PAO Group V). The only thing that matters is it does what oil is supposed to do more often than not. I like 540RAT's blog because he tests oils he receives from people for load capacity and ranks them. It's by no means a comprehensive test of an oil's quality, but it is the one thing that will cause an engine to go to an early grave. You'll see synthetics outperformed by conventional oils plenty in his rankings. So, the reality is any oil of sufficient load capacity that meets the API spec in the owner's manual will work fine in our engines. People really like to exagerate the differences, but the reality is, there are LOTS of available options that will work just fine.

md6380

Internet folklore says the move to 0w-20 was mostly for MPG and emissions, not for protection.

Something interesting, not all Amsoil (and Redline and others) oils are API certified. Amsoil says it’s because some of their formulas have more phosphates than allowed, but phosphates reduce wear.