Originally Posted by LandYaghtLover

Yes. I am not a believer in "snake oil" products, but Seafoam has ben around a long time and it been proven many times to help. Since the intake manifold on my last car is easy to remove, I did so both before and after treatment. Before it was not too bad, but there was certainly oil contamination from the PCV and carbon from EGR. After treatment in the intake I took it apart and it was virtually spotless.

As for oil it does the same, but I am not a fan of thinning out the oil. Most guys run it just before a change. They add it and drive about 50 miles.

http://www.seafoamsales.com/motor-treatment.html