Simpson oil: https://amzn.to/3f7wO7i

In the future I will likely just use Rotella: https://amzn.to/3n8Nb7O That is what I use in my diesel truck and always have it on hand.

Changing the pump oil on a DeWalt pressure washer. It is very simple to do and often neglected.

I bought this pressure washer because it had the Honda motor and learned after the fact that it has the best pump motor as well. The Simpson pump is the best pressure washer pump you can buy.