Toyota 5VZFE with 300,000km. Synthetic or HM Oil?

[nobb]

I think I'm starting to get addicted to this site. I picked up a 1998 Toyota 4Runner with the V6 5VZFE engine 2 months ago and the engine appears to be running just fine even with 300,000kms. Very smooth. I did an oil change 1.5 months ago with Motomaster Formula 1 Synthetic 5W30 (rebranded Shell). I monitor my oil levels regularly and despite the high mileage and synthetic oil, I am not noticing any leaks or consumption issues.

That being said though, I am wondering if it would be worthwhile to go with a high mileage oil for my next OCI or should I stick with my current synthetic? My initial reasoning for doing the first OCI with the synthetic was for its supposedly better cleaning properties, as well as to "test" the engine to see if it would leak (and it doesn't!)

For anyone curious about the Motomaster Formula 1 synthetic, I recently posted a UOA of that oil from my Hyundai Genesis Coupe with the 2.0 turbo. Initial impressions from the report suggest this is a pretty decent oil, no significant wear, and high levels of magnesium (good detergent cleaning properties?). Some possible downsides appear to be a relatively low flash point for a synthetic (365F) and that my viscosity wore down to a 5W20 grade after only 6000km, but that could be due to the turbo.

This Toyota 5VZFE is known to be a pretty tough engine that can probably hit 500,000km on the cheapest oil, but it would still be interesting to hear your thoughts.

 

[Clevy]

I think using a high mileage oil before leaks present themselves is a smart idea. It could prolong the life of the valve guides and gaskets,and the additive packages tend to be a bit stronger and the oils slightly thicker.
Once winter is over I will be using defy in my 260k hemi. It doesn't consume or leak oil but anything I can do to prevent having to tear the engine down is smart money spent.
I have been using liqui-moly motor oil saver though. It's supposed to help seals and valve guides. I like using a 0w in our brutal winters and thought it wise just as a preventative measure to use this stuff.
So far so good.
If you like the oil your already using you could always try this stuff instead of a high mileage oil.
Just a thought

 

[JohnathanDm]

i had a 2002 Toyota 4runner with over 300,000 Miles ran like a clock back in High School.stick with the synthetic you have. I always stuck with 5w30 Synthetic toyota Oil,when my dad was working at toyota.