No not unless you have a problem is the short answer - below is only if your interested in more info.
ashh wrote:do you think I should be Changing viscosity of oil due to getting to the 200,000klm mark now?
I have always run Mobil 1 5w-30 in my Lux and I always cut the Filter open to inspect at every service and never find any metal. I have done random oil Analysis over its life and its always been sweet so I have no intention of going to a higher viscosity because of KLM. Viscosity
---- Im only using Mobil 1 in the below as an example
Ok this gets a little confusing. All good oils you will find are tested to 100 Degree Celsius to give you the actual engine running viscosity and thats so there is a standard for building an engine for clearances and oil sprayers etc. And this is where it gets confusing - at 100c Mobil 1 5w-30 and 0w-40 are almost the same viscosity (about 11 or 12) and your 1GR-FE has a very stable engine temp (if I can remember) at 84c so going up in Viscosity makes no difference in this case --- but at start up the 5w-30 flows better so thats how it gets its "Fuel Economy" status. Also for the record the Mobil 1 5w-30 maintains its viscosity to 200c so if one was thinking of going to a thicker oil will give you more protection its debatable. But going to a "Thicker" oil and one thats actually thicker at 100c than the oil company recommendation tool could actually cause damage to your engine. I always use the Oil Recommendation Tool on the website of what ever my favorite oil company happens to be.
I do this for three reasons - 1: Compatibility with engine seals 2: Correct Viscosity (More Below) 3: If I have a problem I will go back to that oil company with my oil Analysis -- remember theres over a Million 1GR-FE's out there and plenty of Americans who love to sue so they need to get it right.Correct Viscosity from the recommendation tool of your favorite oil.
Its very important as a 5w-30 (or 10w-40) may not have the same specs as a 5w-30 (or 10w-40) from another company.
A very easy way to prove this is go and use the oil recommendation tool on a number of oil company websites and you will find something very interesting. They will happily recommend their Top of the Range 5w-30 Synthetic oil for our 1GR-FE (Or the TRD Hilux) but when it comes to their normal Mineral and cheaper oils they only recommend a 10w-40. I think this says a lot about "Oils Ain't Oils".
In your case the oil company your using is recommending both the 5w-30 and 10w-40 so I presume without reading their data sheet that they are happy that at 100c the viscosity is correct for the 1GR-FE.