Glad it seemed to help

Regarding using a flush product or seafoam in the oil, I would avoid it unless you really think it's necessary. And if it doesn't look bad w/ the valve cover off I think changing the oil on a regular basis is all that's needed.

I've used seafoam in the past, both in the gas and the oil, and it's definitely a good product. However, to paraphrase you, it's not without any risk when used in the oil. In the gas tank there's nothing to worry about, works great, although there are products that will do the same thing for less. Only thing really unique (and one reason it can be put in the oil at all) is that it lubes as well as cleans. That isn't as common in other products but there are at least a couple others.

I've used several kinds of leave-in detergent additives in the oil of several cars. Because they're milder they won't work nearly as fast, and may not ever get things quite as clean, as a true flush product. However, IMO, the risks that can go along with a 5min. flush product or something similar aren't worth it. Seafoam may be safe to leave in the oil according to the company, but if I used it in my current car, I would do it shortly before an oil change and would probably pre-mix it with oil before adding it to the crankcase, but that's just me.