Originally Posted By: edwardh1
Not a car but a mower- why does brigs/stratton say if you use syn oil you have to use the same change interval as dino oil?
odd to me- I thought syn let you extend the interval???
Whats different about mowers?
I don't know about your mower, but the instruction manual for my mower (also has a B&S engine) has the interval expressed in time, not miles or hours. Specifically, it says to replace the oil once a year. Basically, oil degrades over time, regardless if it's mineral or synthetic, so that's why they want you to periodically change it, no matter what oil.
It's no different with cars - most manufacturers, even if they allow longer intervals (in miles) on synthetic, will still require you to have it changed at least once a year, regardless of miles.