Marc780

I just read an interesting comment from an LS owner who happens to live and drive in Ireland. He'd noticed that the recommended oil viscosities were completely different between US and Irish cars, and he wondered why Lexus had two sets of oil recommendations (as do I).

Anyway, here's hard proof from the 2015 owner's manual, Irish edition. Which says you CAN use 5w-30 or even 15w-40 oils if you want to (especially if conditions call for a thicker oil).

I'm trying to think of one good reason not to go by these recommendations instead of those for American cars?


Meanwhile the heaviest oil weight recommended in American LS460's is 5w - 20.

Dave144239

The temperature in Ireland rarely, if ever, gets down to 10F/-12C, so you don't need the lower viscosity on startup.

Striker223

The US manual MUST recommend ONLY the exact weight of oil that will get you the MPG rated on the window sticker or better, the car was tested for MPG on 20 weight so we get stuck with using 20 weight. The 20 weight is more sensitive to heat, and fuel contamination but since stateside MPG is so prioritized that's what they went with.

A more extreme example of this is the JLR 5.0 Supercharged engine, here we get a recommendation of 0/5W-20 and over 10k change intervals.....and these engines are known to blow up and kill rods/chains etc. That's because when you move to a more appropriate for the heat/strain/load oil like a 0-30 you lose 1.5-3 mpg and we can't have that! My dads L405 has 73k miles with a new engine installed at 67k due to oil failure, fantastic way to save the environment by requiring a new engine every 70k or so right!

THEunderPSI

^Yep. The recommendation for such thin oils is based purely on mpg's. I run Mobil 1 European 0w-40 in all my gas engines. Great oil.