Hello
I read these high mileage oils can damage engines like expand seals and make them break down faster. Is it true should I stick with full synthetic or is high mileage full synthetic version safe and actually better?
If your engine is working fine and doesn't leak or burn oil, then don't try to fix what isn't broken. Regular oil changes is the best thing you can do for the engine.
I find it is more about changing the oil on time than anything else.
Either one will work fine. The high mileage oils have more anti-wear and friction additives that are supposed to compensate for a somewhat worn engine. Honestly, it doesn't really matter - any of the major oil brands (Valvoline, Castrol, Quaker State, etc.) make great synthetic oil. Use the viscosity that your car's engine calls for and normal full synthetic oil will work perfect.
"anti-wear and friction additives" sounds a lot like marketing language for thicker oil
Just stick to full synthetic and stay on top of your oil change intervals (every 5,000 miles).
Are you experiencing oil burning/oil consumption in between changes? If not, stick with major brand regular or synth.
