Regarding: As a follow up to MM's video link regarding oil viscosity specs, I'm curious to know if anyone has changed-up their oil weight to a lighter specification.

Background: Short of the past decade, Toyota/Lexus changed their vehicle oil specifications from 5W-30 to 0W-20. The general consensus is they did this with little to no change to their engines. The aim is better gas mileage, and the justification is that modern, synthetic oils have been improved to the point where a lighter weight will not result in greater wear. Some dealer shops have even started using 0W-20 oil in older engines (from the 5W-30 era).

Question: Have you done this in any of your older Toyota/Lexus vehicles, and if so, have you noticed any good or bad consequences?

Note: Not looking for advice to stick with what's specified in the owners manual.

 

I wouldn’t. A 1-2% improvement in fuel economy on any individual vehicle is not even noticeable. Manufacturers are doing it because multiplied by hundreds of thousands of vehicles per year, it makes a non-trivial impact to their overall CAFE score.

 

Lexus and Toyota also moved to 10,000 mile oil change intervals as well (aside from a few cars). I think the F cars still use the 5w30.

 

There is one circumstance where it might be beneficial to vary from the original factory-recommended viscosity, and that is on old engines with worn rings / valves / bearings and other places where oil can leak or be consumed. Sometimes, using thicker oil will help compensate for the increased-clearances in the engine and prevent as much of the oil from being burnt or leaking. That, of course, is a Band-Aid fix that doesn't get to the root of the problem (new engine parts or an overhaul/rebuild)....but it can help for limited periods of time if one's budget does not allow for a major repair.

 

I know that I was happy running 0w30 in a turbocharged 1986.5 Supra (10w30 spec) and I did experiment with 0w20 in a 96 LS400. Never had any oil related concerns with either car.

 

If I switch to a lighter weight, I would err on the side of caution and stick to the 5K interval, although, that would be another way to save $.

 

In regards to the burning of oil, I`d wager using thicker oil is quite the gamble. If the oil is burning specifically since its got say not enough oil drain holes, using thicker oil is going to result in increased wear and tear. In that scenario you actually want to keep the cold weight as thin as possible and the hot weight to spec.

 

With a turbo, did you ever run 0w40?

 

I have not changed any thing. My 2007 IS 350 I bought new had 5w-30 on the oil cap & I always used Castrol 5w30 in it.every 8,000 miles Sold it when it got to 96,K miles. Bought my 2015 GS350 F-sport in 2015 & it's oil cap calls for Ow20. I use Castrol edge 5w30 in it too & I plan for this to be the last car I ever buy.

 

Never did. It was an NA-turbo conversion too on the 7M-GE engine, and I didn't even bother connecting the water lines to the CT26, just oil cooled. Ran great. I used "German Castrrol" 0w30 which had a stellar reputation back then. The oil color was green too!