I was just wondering if I should switch to a thicker oil once my car hits 100k. or should i just stick with 5w-30? through out? i was thinking about going 10w-30 once its 100k.

 

stick with 5w-30. Nothing really changes at 100k miles.

 

Have you noticed any negative change with using the 5W30, because if not stick to with what you have.

 

Definately no need to go thicker.

I still use 5w-30 synthetic and I'm at 204,000 miles

 

i've heard of ppl goign to heavier weight motor oil when and if their cars get higher mileage or start burning oil.

any truth to these urban legends?

 

thats what im hearing and im just trying to find out if its true or not.

 

People usually use thicker oil when their engines starts consuming more oil than it's suppose to. If your engine is fine, no need to switch.

People do not use higher-viscosity oil in their engine just because their engines are older...it's because the engine isn't in tip-toe shape. It's a band-aid a problem.

 

All a 10W will do is thicken the oil at startup which will wear out the engine quicker. You may even want to switch to a good synthetic, but do your research first.

I've actually started using Amsoil 0W-30 on my '00 LS400 (55k) and increased my mileage 10%. However, you don't want to use a thin synthetic on a car with too many miles due to "seal seepage". So far, So good

Stick with what's recommended.

 

where did you hear that?

 

ideal viscosity for lubrication is 10 cSt. Oil that flows well, not thickens up, at cold lubricates engine better.
10w-30 by SAE weight classification is thicker than 5w-30 before engine reach operating temperature. And 5w-30 is already too thick for engine startup, adding even thicker oil such as 10w-30 is not good for the engine.

A good place to research is to take a look at 40 degree C viscosity published in data spec for a 10w-30 vs 5w-30 oil of the same brand and see how far they are from 10 cSt. That difference is even more magnified at lower temperature,which is more realistic for us since no one starts car @ 40 degree C.

 

Changing to heavier oil is done when an engine is older and oil pressure drops below standards, it will bring the pressure back up.

It can also be recommended when going FI, but not when it is cold outside.

 

noob question: i'm planning to change the oil on my car, how many Liters do i need?

 

10%

seriously?

interesting...

 

You can usually find out the info by looking at your owners manual. If your SC400 is like my GS400, then you'll need about 4.5-4.7L. Either way, you should always gradually check how much oil you have before putting in more. I bought a 4.7L jug and it was enough for my oil change.

 

If your car is stock then just stick to whatever comes from the factory. For me, I'm actually thinking about putting in some Amsoil Synthetic 20w-50 severe service racing oil. With a turbo'd(high oil temps) and high revving setup...the oil tends to thin out big time.