superdenso

The following represents my words: "Which means others experience or are concerned about oil use and transmission issues (25K views). 100K LS's were sold in the US *Those % refute the chemistry data. "

SW15LS: Four paragraphs to say you support your buddies? My statement holds and your passionate response will not scare. LS is a beautiful machine and 250k views makes a statement.
Spoiler Alert: Running forums for 15 years&still getting it wrong doesn't surprise anybody. I read your responses in each paragraph and you are consistent.

SW17LS

LOL, whatever you say pal.

Last thing I will say, all the people you're arguing with who are not concerned with nor have they experienced oil consumption (such as me) have registered page views in this thread as well. That's my point.

superdenso

SW15LS: You seem like a pretty cool guy. There is no argument. Use the oil you like. I simply present a dissenting opinion. Research why 5w20 oil is recommended. Ask about the tradeoff/sacrifice for the increased mpg. Be well and enjoy your ownership experience.

SW17LS

The 5W20 is recommended for fuel economy. No argument there.

superdenso

What is the tradeoff for that "alleged" fuel economy.

SW17LS

I don't see any conclusive evidence that there is any trade off. You have a few owners that have complained about oil consumption issues, and if you look back through the threads you will clearly see it is only a few people actually reporting issues. Nobody who reports reliability data has anything to say about oil consumption. I had a long talk with my mechanic about the 460 before I got mine, he was a Lexus master tech for 16 years and now owns his own Lexus focused shop. We discussed common issues such as control arm failures, but nothing about oil consumption.

The 460 is not new, it's been around for 9 years. Plenty of high mileage older 460s, if there were a significant oil consumption issue, we would see that here on the largest Lexus forum. There's a discussion here, but very few people actually posting and reporting problems.

In any event, even if the engines consumed a little oil, what if any damage or longevity issues are we seeing? There really are none to be found.

So...I would argue there really isn't any trade off.

roadfrog

FWIW, I am now into my current OCI of about 7k miles and I'm now just about to add my first make-up qt of oil to bring the dipstick up to the full mark. This is my third run of TGMO 0W20 with the last OCI's being 6k miles. Previous to that, I was using 5w30 (various brands of synth), and required adding a qt every 1.5k miles or so.

In summation, since changing to 0w20 (from 5w30), my oil consumption has dropped to nearly zero.

Doublebase

Anyway we can get the name of this thread changed? I just don't want people to come on here and see "LS 460 oil consumption issue", because they're going to get the wrong idea about the car. These cars are not known for oil consumption problems, I know I don't have it, and I know many on here don't either. In fact I'd say this is the tightest engine I've ever owned.

Devh

I for one do not believe there is any significant difference in economy between the 20 weight oil vs a 30 weight oils. What I do see or better oil potentials with the thinner oils in a few key areas.

1. Better start up protection
2. Better VVT operation
3. Strength of the base oil is better and less susceptible to mechanical shear because it requires far less viscosity improvers then a 30wt oil.

As engines get tighter they require lower viscosity fluids to avoid fluid friction.

In the future we may even see 0W – 10 oils if we stay in the same paradigm of combustible engines.

superdenso

[QUOTE=Devh;9175518]I for one do not believe there is any significant difference in economy between the 20 weight oil vs a 30 weight oils. What I do see or better oil potentials with the thinner oils in a few key areas.

1. Better start up protection
2. Better VVT operation
3. Strength of the base oil is better and less susceptible to mechanical shear because it requires far less viscosity improvers then a 30wt oil.

Devh: Not changing the Trans fluid and using 5w20 will yield results. That you can believe. 5w20, 5w30, and 5w40 are the same at start up...call Mobil 1, Castrol, or Royal Purple and ask. You need vvti and downshifts because of your fluids. Stop into a Dealer and test drive a car that has not been adjusted by service. The difference is your fluid maintenance philosophy.

Devh

Where do I begin. I said the thinner oil in reference to 20wt oils has better oil potentials.
Why, not because flowability is similar at cold start up temperatures determined by the W (winter) number as you pointed out. It's primarily because the oil with the least amount of spread has the highest potential to have a higher viscosity index because less VI improvers are needed.
Why is Viscosity Index important, primarily because it's what determines the oil stability as the temperature changes. It's one of the holy grails when it comes to reducing start up wear because it resists thinning as it's being heated to provide right amount of viscosity protection between parts especially during a cold start. This is one of the major contributes apart from additives that reduces start up wear.
Most 0W-20 oils have a higher VI then 30 weight oils and Toyota 0W-20 has the highest viscosity Index out of all oils.

There are several sources that point this out but this link explains it best.
http://www.bobistheoilguy.com/forums...76#Post3147776

Devh

I would really like to hear how you measured 10% better fuel economy with running 5W30.

I didn't know that you could change the compression ratio with running different engine oil.

superdenso

Devh: Johnny5...you require input (just a joke The question about compression and oil makes me wonder if you know what you're saying

http://www.aa1car.com/library/oil_consumption.htm
http://www.mikebentley.com/oilburn.htm
http://www.machinerylubrication.com/Read/518/motor-oils
http://www.yotatech.com/f2/problems-...burning-55462/

Devh

You made a generalized statement in regard to a normal engine where you would achieve better MPG due to increased compression. Now you pull the abnormal condition to blanket your fallacy.
If the piston rings are within normal tolerances then there should be no deviation in compression with whatever oil you use. This can be proven on a wet compression test.

As I said "I didn't know that you could change the compression ratio with running different engine oil."
This is in the realm of a normal functioning engine not an abnormal one that has it's rings shot that may restore compression. It also does not change the compression ratio because that is a measure of air volumes that can only be changed by mechanical means or deposits not by engine oil.
http://cochise.uia.net/pkelley2/DynamicCR.html

Quoted from your link.
Significant ring and liner wear would mean your engine is shot. It also means that you will not see 10% increase in MPG as you have stated. Those two do not go hand in hand. You would also have to prove that all the cars are in an abnormal condition from the factory for your argument to have any merit which is clearly not the case.
At this point in time the engine would be burning large quantities of oil that may be visible.

Most all oil consumption issues is generally a problem with the oil control ring where the squeegee function is compromised by excessive clearances. This will allow oil to get past the rings on the down stroke into the combustion chamber. Switching to a thicker oil will buy you some time but it is only a bandaid and not a long term solution for a worn engine.

You still haven't answered my question on how you calculated 10% better MPG using thicker oil.

superdenso

Devh: You just have to stick with 5w20.