Fuel And Oil

[RX350lover]

I made an interesting experiment. In a 1998 non-Lexus car with 78,000 miles, in which I used Premium fuel and is 95% highway driven; I added a bottle of STP complete fuel system cleaner ($5 at Walmart) and when I did the oil change earlier today, the oil was more reddish in color and the texture of the oil was a little bit different. Like if some powder had been added to it.

So it seems that despite using Premium fuel, it does leave a good amount of deposits inside the cylinders. The car is in 'perfect' shape and at every emissions test I score about 90% below the limts allowed.

[RX350lover]

Regarding the Lexus RX 350:

Since switching from dino oil (at 20K miles & 2 1/2 yr old) to synthetic; and after driving no more than 100 miles, I can see that the oil that was originally clear and transparent is now moving to a yellowish color. Removing the sludge left from the dino oil. It really doesn't make sense to use dino oil anymore. Except during the break-in period.

[pj8708]

Regarding the Lexus RX 350:

Since switching from dino oil (at 20K miles & 2 1/2 yr old) to synthetic; and after driving no more than 100 miles, I can see that the oil that was originally clear and transparent is now moving to a yellowish color. Removing the sludge left from the dino oil. It really doesn't make sense to use dino oil anymore. Except during the break-in period.

I only have 3,340 miles on my ES and when I change oil at 5000 I'll use Synth. I sure this has been posted before, but what type of oil in put in the engine from the factory?

[RX350lover]

Regarding the Lexus RX 350:

Since switching from dino oil (at 20K miles & 2 1/2 yr old) to synthetic; and after driving no more than 100 miles, I can see that the oil that was originally clear and transparent is now moving to a yellowish color. Removing the sludge left from the dino oil. It really doesn't make sense to use dino oil anymore. Except during the break-in period.

I only have 3,340 miles on my ES and when I change oil at 5000 I'll use Synth. I sure this has been posted before, but what type of oil in put in the engine from the factory?

I don't know about the ES, but when I was the Lexus dealer getting my $180 synthetic oil change in my 2009 RX 350, the service adviser informed me that Lexus is only using synthetic oil in the RX 350 since MY 2010.

I guess it would be logical to assume that possibly all Lexus models since 2010 use synthetic only. I don't know. I guess asking your dealer will provide you the answer. AFAIC, dino oil should have been removed from circulation more than a decade ago. One only needs to look inside an engine that uses synthetic versus dino to understand why. Synthetic is far, far superior to dino oil.

Some 10-15 years ago, I remember another cars manufacturer using dino during break-in period because it was doing a better job at 'breaking' a new engine. And would switch to synthetic at the first oil change. I don't know what they are doing now. I haven't kept up with what is happening.