A Yanmar GM user asked the following question, and it's a good one…
IIs there any advantage to running straight #30 diesel rated oil as compared to 15W40 in these older 1980\’s engines?
Thanks,
James (who sails a Bayfield 32C in Ontario, CANADA)
![](https://saltwaterdiesels.com/wp-content/uploads/2020/02/wave-break.png)