Hi all,

In my country most believe that with mileage oil grade should be changed i.e.

For my Lexus RX 3rd gen I always use 0W-20 as per manual. As we don't have any official dealer we use any mechanics to change the oil. And most mechanics out here believe that oil grade should be changed after 70-80K miles to 5W-40 at least. And I don't believe on this. It was designed to work with 0W-20 and I don't want to mess up with my oil.
Does anybody have any idea about this? It would be good to read scientific writings if it is true.
Thanks in advance.

 

Although I haven't spoken to Lexus about the RX, I can tell you that I have spoken to them about the SC430 I have and they advise against changing the viscosity at any point in the life of the vehicle. In a less round about way of answering your question. Lexus says don't do it!

 

the tolerances on the 3rd gen are tight..use the specific oil and oil change intervals in the manual . Thicker weight oil is a bandaid for loose tolerances and/or worn out engines.

 

DweN, I come from similar country and common sense. Common sense tells me that tolerances get largerr from simple mechanic use and thin 0W20 oil eventually becomes too thin for them. It's common sense. I find it naive to believe that engine will be factory tight after 80 - 100 thousand miles. Telltale sign will be increased oil consumption or oil getting darker faster. Or, even worse, cold start rattles and rocker noises appear.
As I am sitting typing here, and we owned many used cars, well over thirty, every time I fixed most of those issues by switching to heavier weight. 5W20 then, eventually, to 10W30. I am not sure why in your country they switch to 5W40. Oil should have least difference between the two numbers, so 5W30 is better than 5W40. Or,I simply add Lucas oil treatment for high mileage engines, what thickens oil. On trucks, I simply jump to 10W30.
If you were to look at oil choice charts, they don't go by mileage. They go by outside temperature. Oil for Alaska will be quite different from oil for say equatorial Africa.
That's my years of well running engines experience. and common sense.

 

OP, unfortunately, this is an endless debate topic, with many technicians, mechanics and people with very high mileage cars saying that a change to a thicker oil may be warranted on occasion. But then again, the car developers and other master mechanics saying: "don't do it". I have and have run cars between 200-300k miles w/o issue. But this is not an endorsement of the practice.

Unlike many Americans, those of us who grew up in other countries have a much less penchant for disposing of things as quickly as they do here in the US, often referred to as the "disposable society (reference to cars, bikes, spouses, homes, old buildings, etc.). My wife gets a car every 4-5 years...I keep mine about 15-20 years on average with mileage well above 200K miles.

So, I really don't have an answer. I know many old timers in the US would put thicker oil in the 57 Chevy's. 1967 MuStangs, and old VW's as a way of buying time (often years).

 

Is there a problem or just an itch to move to a different grade of oil. I would suggest to follow the specification and stay away from additives till there is a need.

It does amuse me when folks interchangeably use flow grade with thick/thin ..ess of oil. There is some basis for that but the numbers are about the flow rate and temperature.

Salim

 

 

I wouldn't change oil grade just because of mileage. If you're engine isn't burning oil or otherwise consuming it then stick with the recommended 0w20. Urkoz changed oil viscosity when he had an issue, which did fix it from how I read his post, but didn't appear to change grades just because of mileage. There is some discussion on Bob is the oil guy (bitog.com) forums about this and high mileage oils. I have a GMC truck that didn't burn or leak any oil then at 105k miles decided to switch to high mileage type oil just based on mileage. (I live in the high desert and it usually gets up to the 117 degree mark every summer). Unfortunately I think I caused my oil consumption by doing that within 10k miles...the high mileage oils have additives that cause the seals to swell a little more, to take up the slack from a worn engine. Well apparently not every engine wears the same, much depends on maintenance. I changed oil every 3000-4000 miles, oil analysis showed very little wear but my stupidity decided to try a high mileage oil and actually made things worse. The lesson is, if it isn't broke don't fix it.
Sorry for the long diatribe

 

I think your argument is true. In my country I hear about a lot of engine problems. Most of the problems are with newer model cars (not older than 2010).
And most drivers believe that oil grade should be changed after 70-80K miles. And I personally think those problems come from the change of grade that initially wasn't designed for. I will stick with my oil change interval and same grade.

 

Use UOA's to determine how effectively your oil is holding up and how your engine is doing. I'm not sure what options exist in your country but here in the US Blackstone & other labs are popular options.

 

I wish, y'all spoke Russian and watched my beloved guy on Youtube, where he tears modern engines apart and points towards design flaws. With a firm opinion that they are designed to become obsolete by roughly 60 000 miles. Unfortunately, his opinion is based on facts, not feeling. Failing chains, failing hydraulic tensioners, inability, per design, to machine engine heads, aluminum engine blocks with rubbed off pistons coating, ill designed coolant passages, etc, etc... Alll that across the entire industry, as he does Mercedes, BMW, Japanese, Volvo, French engines. According to him, and I do agree, era of reliable engines and cars ended mid 90s.
That said, business is business. Car manufacturer is NOT interested in making a vehicle that runs forever. This does not make any business sense. They need to sell, not to rest on laurels of perfectly reliable vehicles.
Sorry for hijacking the thread, hope Salim won't get angry. But, there is an interesting document that you can't find here in the US. You can in say Russia. It is called "engine resource" statement. For how many miles engine is guaranteed to last by manufacturer. I saw that spec for Russian market engines and I absolutely doubt, they make them different from ones for US market. But that resource is amazingly short. Somewhere around 100 000 km average.
Why did I go into all that philosophical conspiracy discussion? Because I do believe that there is no business sense for manufacturer to tell owner to follow common sense and go with different oil viscosity, as metal moving components wear out. Rings leading edges, bearings coating, carbon build ups on valve seats, seals cracking ow wearing out. It's mechanical device, not made out of adamantium, so it naturally goes that route.
That's my dos centavos. Based on experience, not what lawyers wrote in user manual.

 

That is pretty funny. Cars are more reliable today than ever. I assume your are trying to be funny, if not, I will discount everything you say on this forum from here on out. Obsolete at 60K miles. You have got to be kidding. They are just getting broken in at that point.

 

The Toyota offices would be closed down from mass ritual suicide if the engineers would realize all they can attain is 100,000 km/ 60K miles on average out of a car. The 3rd gen 2GR-FE's are now reporting in at over 300,000 miles....with continued regular maintenance they may hit over 1/2 million miles or more. Time will tell based on the design and willingness of owners to upkeep their vehicles.