Hey Scotty! first, thank you for sharing your many years of knowledge. Your videos are both entertaining and informative. Here's a question I'm not sure you've answered before.
Why is it recommended to replace oil at X miles OR X amount of time. Oil doesn't expire like milk, so what if it was a low use 300miles but, let's say 8 months has passed. why should I change that oil? it would be fine stored on a shelf at the store.
thanks again for keeping us revving!
Well you either change it every 5,000 miles with synthetic oil or once a year
it would be fine stored on a shelf at the store.
oil is fine in a sealed climate controlled bottle.
oil in your crankcase is exposed to atmospheric air, moisture, combustion vapors, raw gasoline, and various other contaminants... and mainly, high heat.
Why is it recommended to replace oil at X miles OR X amount of time. Oil doesn't expire like milk, so what if it was a low use 300miles but, let's say 8 months has passed. why should I change that oil? it would be fine stored on a shelf at the store.
That's the key, it's not stored on the shelf at the store anymore. It's in your engine, exposed to the elements. The crankcase isn't a sealed unit. Combustion also produces acidic byproducts that get into the oil (NOx), and it's up to additives to maintain neutrality. It's also being exposed to condensation, etc.
