I've always wondered whether to use 5W30 (as in the manual) or 5W20 (as recommended by some). I came across this thread with a chart from Lexus Canada. Why would the IS350 be different from GS350?. I would have thought it should be the same since they share the same engine.

http://www.bobistheoilguy.com/forums...2467275&page=1

 

Best to use what the manufacturer recommends, especially if you have any warranty left, as they would use that as a reason not to cover a repair.

 

Take note of the use of lighter weight in correlation with MPG requirements. A little secret in the auto biz is using lighter oils to help with gas mileage.

 

Can't say it is a secret!

At hot temps I don't see it making much diff at all, but at cold, huge difference.

I have been studying the xW20 oils and it is hard to justify not to use them.

 

I use 5w-20 in my 3GS GS430.... No leaking issues at all, engine runs smoother, much easier to get higher MPGs, the list goes on and on against Mobil1 5w-30 IMO. (I'm using Redline 5w-20

 

Anybody using 0w30 like the newer Lexus vehicles? Any reason?

 

0w20 here (2GS4), cold weather performance main reason. Read up on Dr. Haas on engine oil, you won't want to run anything thicker than 0W20 again.....

http://ferrarichat.com/forum/faq.php?faq=haas_articles

 

Even when summer temps exceed 110 degrees?

 

using 5W30 im in the south where its hotter. Would use a lighter one if I was up north more

 

Read Dr. Haas's articles on it. 0W20 year round, even in the heat. If RACING where oil temps exceed 300F then you ~might~ need to go up a grade. But on the street, the oil temps rarely go up to 300F, then it isn't needed.

Seriously, take the time to read the articles.

The key is oil temps. What are they? What do they get to? Looking at the oil color after 10k miles on Mobil 1 0W30 AFE when I ran it, oil temps do not get high. The ring temps are the typical hot spot on any engine.

 

holy crap that was a long *** article...so I guess i will use 0W20

 

haha me too i skimmed thru then realized it was never ending. 0W20 it is from now on

 

If you are going to do some track time, sure, run thicker, but on the street oil temps are largely stable if not on the cool side in winter months, likely never getting up to 250F. I am running 0W20 in my wife 2000 Park Ave Ultra and she has 201k miles on it, with 0W20 in it the last 10k or so. No issues at all.

On my Lexus, no additional oil usage, on my Buick, a little, but no way to know if it is "normal" for the age, maybe 1 quart every 6k miles on the Buick, maybe 1/2 quart every 15k on the Lexus (I had a small leak that I fixed).

Lexus relaxed the bearing specs on the GS460/LS460 compared to the GS400. And the GS400 called for 5W30. I can't imagine running thicker as tight as the GS400 is. It has very tight clearances.

 

I've been trying to tell people to run 20w oils in their cars for the longest time.... Finally you guys read the articles and are all jumping ship to the 20w oils :P

I'm glad though, at least everyone knows the background to oil bases and whatnot. thumbs up to you RamAirRckt !

 

I've even shot a few questions to Dr. Haas directly, really nice guy, knows his stuff.

I won't turn back.... Been using 0W20 Amsoil for nearly a year now. Tried petroleum 5W20 first to see how it went and then went 0W20.