High mileage oil in new car

[Spector]

Supposedly HM oils have seal additives that cause them to swell which is fine if you have a leak or perhaps consumption. In an engine that is running fine the use of HM is not indicated IMO and would be like taking a blood pressure med when your pressure is fine but thinking that you will be ahead of the curve be taking the med early on in life.

 

[bigt61]

How do HM oils stop leaky seals from leaking? They make them swell up slightly. Do you think this is a good thing on a new car? I don't. Use HM oil when it's needed - that's it.