This is a really good article by AMSOIL on 5 myths of motor oil that are not true!
- When motor oil turn black it must be changed
- You must change oil every 3000 miles
- You can’t mix synthetic and conventional motor oil
- Once you switch to synthetic you can’t go back
- Synthetic oil causes engines to leak oil
Also there is a good video with Gale Banks on “what’s in synthetic motor oil’!