Shell Rotella is a high detergent oil. It's made for diesels, but I put it in everything. Disclosure I used sell it. I've had mechanics tell me that they could tell a diesel engine had been running it because of how clean it was when they tore it down. However if you run a high detergent oil in a really dirty engine, it will break all that crud loose and clog up your oil filter. So when I get a really dirty one, (like the one I'm working on now) I drive it awhile, then change it again. And check frequently after that. Compared to swapping an engine, oil and filters are cheap.