Why is it necessary to change vehicle oil regularly, and not just change the filter and add new oil as needed?

Question

Why is it necessary to change vehicle oil regularly, and not just change the filter and add new oil as needed?

In: Engineering

Answer 1

You can do that short term, but eventually you have to do a complete change. When I drove 3-4 k a month, I would change the filter every month. I would do a complete change,with filter, at 30k to 40k miles. This was on Chevy Astro vans and a Ford Flex. They all went over 200k miles, with no problems. I only used full synthetic oil.