austinav

Now, I am pure believer in using original parts for my vehicle including engine oil.

So my 9 year old running great car which i had imported from USA is running smooth and silent, except the annoying dashboard squeaks when going over rough surfaces.

Because I owned a 2010 RX350 which recommended the 0W20 oil, so I thought it is a good oil for GS300. I was so wrong.

I loaded this oil TOYOTA 0W20 engine oil for 8 months when I got the car (about 3 oil changes) But the oil consumption is 1 quart for approximately 3000 to 5000km. Reading the manual, it stated it is a normal consumption. I was shocked because I never have issues with high oil consumption in my previously owned cars. This thin oil also cause a slight backlashing sound when you release the accelerator and step on in slow moving traffic. And the starting sewing machine cam gear sound is also very pronounced, loud and last for good 10 seconds before it silenced down.

Checked by Toyota (there is no Lexus service center in Cambodia yet!) and the technician said there is a slight top header gasket leaks but that is not the likely cause. And there is no smoke issues from the exhaust.

So, I sense I should revert back to basics. Used the recommended Toyota 5W30. Approaching 3000 km and the oil level is within the 2 dots and I haven't need to top it up.

Not only I noticed the backlashing sound when you release your accel pedal and step on it was significantly reduced, the starting sewing machine cam gear noise is almost instantaneously gone. (it last a 2 to 3 seconds and less noisy!)

Do I get poor oil mileage? No, I can get 31~32 mpg on highways ! I have pics to prove it. So I am still monitoring it but I think i had nailed the issue to a certain extend. The next 2 maintenance I would like to proceed is silencing the dashboard squeaks and the header gaskets which I had ordered to Toyota already. Hope you guys using thinner oil with the oil consumption issues can give it a try and share the experience..

BinaryJay

So we should use the manufacturer recommended oil weight? Good to know.

blue00

Well it might be different between Camodia and Canada, but here Lexus on the Park and Pickering Toyota suggested and put 0w20 in my 10' GS350.

Note that I do not have any low mileage or oil consumption issue (yet)... Noise wise I am having a hard time qualifying what is normal when it comes to the OCD fixation on small variations. I have a hard time if a specific "sewing machine noise" or rumble, is due to the -30 temperature, or due to my lead foot....

As for the squeak, if you mean the "chirp" that comes from the plastic on the exterior of the windshield, I found it comes from 2 specific points (near the driver side wiper attachment, and almost in the corner at the passenger side) when there an accumulation of dust/grime under the plastic, I just pulled the black plastic on the outside slightly away from the windshield and squirted a little bit of teflon chain lube on the glass.

austinav

I think we are looking at the differences of engine types and vintage year, because I am aware of the early batches of Gen 3 GS300 (DOM late 2005). The car I have was actually imported from USA in 2014 after the only owner in USA had clocked 92k miles and religiously maintained by Lexus there.