[floridanative]

I really hate to start an oil thread, but here goes anyway...

I've been using Mobil 1 full synthetic in my 2007 Sienna (we bought it new) since it had 5000 miles. I'm now at 146,000. I change the oil every 5000 miles whether it needs it or not. It has never used any oil between changes.

Should I switch to a high mileage synthetic? When?

A big part of me says don't fix it if it ain't broke and to just stick with the Mobil 1.

-Mike

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[fibber2]

One of the additives in a "high mileage oil" is seal conditions intended to help valve guide seals and rings work better in slowly degrading engines. They also help regular assembly gaskets swell to prevent external oil leaks.

My general guide is that if your engine isn't showing signs of either internal or external leakage, there probably isn't a compelling reason yet to mess with a different formulation.

There came a point where my old Subaru flat 4 clearly told me "it's time!". I have to say that the reduction in external oil leaks was very evident after a few changes.

 

[Joe H.]

You should start using high mileage synthetic oil at 150,000 miles.

 

[97trophy]

Depends on how well your car has been looked after. Low mileage regular changes sure 150k miles. If not sooner would be a good idea.

One answer does not fit all.

 

[Joe H.]

Of course, you’re correct. Depending on factors such as severe usage or conditions, some might benefit from starting sooner. The time to start using high mileage oil at minimum of 150,000 miles is the opinion of a dealership mechanic/technician, not mine. But there again, it’s still just an opinion, but it’s based on his experiences that most problems that might benefit from using high mileage oil start to occur after 150,000 miles, so I would tend to believe him.