Originally Posted by skoh

0W-20 is required.
Due to the low viscosity, 0W-20 is generally a synthetic oil.

See attached oil spec from the owner's manual.

Originally Posted by mitsuguy

You might not have, because it is technically incorrect.

Originally Posted by mitsuguy

You might not have, because it is technically incorrect. Many people assume that is what it means, but it is not.

in a 5W-30, the oil flows like a 5 weight does, but protects the engine the same way a 30 weight does... the second number is basically the oils "stickiness" and describes how well it clings to engine parts - if using a straight weight oil, the thicker the oil, the better it sticks to bearings and journals, however, with multigrade oils, we try to make the oil flow better, so it comes out thinner, but we still need it to cling to the metals in the engine to protect them...

Similarly, a 0W-20 has an oil flow rate of a 0 weight oil, but the protection of a 20 weight oil...

it has nothing to do with hot or cold, other than the obvious that a 5 weight oil flows better than a 10 weight oil when it is extremely cold out, and a 30 weight oil protects better than a 20 weight oil under extreme high temperatures...

There is only one place this argument about long oil change intervals doesn't hold up... Contaminants. I know you say change the filter, blah blah blah, but what about fuel and water contaminants - oil filters do not separate these. Vehicles that idle a lot or always go on short trips many times don't vaporize the water that has condensed inside the engine, thus contaminating the oil. Similarly, on cold starts, before things are nice and warm, a certain amount of fuel will be washed past the rings and into the oil... Enough cold starts and you have severely contaminated oil. Now, if you go and have some nice long trips, it may burn / vaporize all of that, but that is just one reason why your theory doesn't hold up for everyone. It may work ok for you, but giving that kind of advice to someone who doesn't know there are differences may be bad for their engine in their particular climate / driving style may not be right...

Originally Posted by xfirechief

If you have never been to WI. it does get hot here in the summer too. Back in 1988 I believe we had 33 days about 90 degrees.

AMSOIL has a 0W - 20 & a 0W-30 too.
And AMSOIL is made in the good old USA. "No Iran in the can."

Originally Posted by DNC

Speaking as someone who has driven vehicles the distance you guys are talking about (both gas and diesel/new and older) and having used synethetic oil in farm tractors; I would rather use conventional oil and change it more often than push such limits as you describe. I came to this conclusion after many conversations with a Mobil oil rep. I met in the Mercedes club and by my own experience of twenty years.
Now having said that everyone must do what they are comfortable with, I just would not buy a car with that kind of history. I am very enviromentally conscious and believe preserving a vehicle by practicing good servicing habits saves more resources than pushing oil limits and causing earlier replacement, not to mention more efficiency during operation and better emission results. Again, everyone must do what they are comfortable with.

Originally Posted by DNC

After rereading my above posting I think I may have given the wrong impression. I do use synethetic oil, Mobil One and Mobil Delvac One. I just do not push it to 10,000 miles between changes. Before doing that it would make more sense for "me" to use conventional oil and change at 3,000 mile intervals. I have come to this conclusion after much thought and extensive experience with many vehciles. This is what works best for my vehicles with the factors they face.

Originally Posted by The G Man

I think anybody can find documentation from the oil manufacturers that claims their oil can last XXXXX amount of miles. I like to see a indepenent studies' results, an oil analysis report. Oil will break down sooner or later rather if its dino or sythetic. If you use sythetic and change your oil longer than Toyota's recommandation and have a oil related problem, which is very very unlikely by the way, good luck if you try to get a new power train form the oil manufacturer. The oil company will come up with more excuse than your dealer will

Originally Posted by mitsuguy

...in a 5W-30, the oil flows like a 5 weight does, but protects the engine the same way a 30 weight does... the second number is basically the oils "stickiness" and describes how well it clings to engine parts - if using a straight weight oil, the thicker the oil, the better it sticks to bearings and journals, however, with multigrade oils, we try to make the oil flow better, so it comes out thinner, but we still need it to cling to the metals in the engine to protect them...

Similarly, a 0W-20 has an oil flow rate of a 0 weight oil, but the protection of a 20 weight oil...

it has nothing to do with hot or cold, other than the obvious that a 5 weight oil flows better than a 10 weight oil when it is extremely cold out, and a 30 weight oil protects better than a 20 weight oil under extreme high temperatures...

There is only one place this argument about long oil change intervals doesn't hold up... Contaminants. I know you say change the filter, blah blah blah, but what about fuel and water contaminants - oil filters do not separate these. Vehicles that idle a lot or always go on short trips many times don't vaporize the water that has condensed inside the engine, thus contaminating the oil. Similarly, on cold starts, before things are nice and warm, a certain amount of fuel will be washed past the rings and into the oil... Enough cold starts and you have severely contaminated oil. Now, if you go and have some nice long trips, it may burn / vaporize all of that, but that is just one reason why your theory doesn't hold up for everyone. It may work ok for you, but giving that kind of advice to someone who doesn't know there are differences may be bad for their engine in their particular climate / driving style may not be right...

Originally Posted by The G Man

Most synthetic oil will last 15000 miles, its the filters that wont last that long. Most european cars have been using oil filter that are 2 or 3 times the size of Japanese oil filter in order to prolong the oil change interval. Even with the bigger filter, they are still only recommanding 10K change interval.

Originally Posted by The G Man

The problem is that owner who drives very few miles per year and still go by the mileage interval. Oil sitting in the pan will contaminate over time.

Originally Posted by The G Man

How big is the Cayenne's oil filter? Most European cars have longer oil change interval due to the larger oil filter. Synthetic oil will last much longer than 5000 miles, but that small filter in the Lexus engine will not. Since Lexus had all those oil sludge problem in the pass, I guess they are just playing it safe and change both at 5000 miles. BTW, is this the 1st Lexus engine that requires synthetic oil?