Under normal conditions Mobile 1 will keep an engine clean. Sea foam will clean a dirty engine very well. To keep this from happening in the future, you need to find out what happened to cause the sludge and fix it. It could be not changing your oil, overheating, excessive wear or a low grade oil that won't last the proper duration for your oil changes. My 265,000 mile engine is clean with Mobile 1 high mileage 15,000 mile oil with oil changes every 8,000 to 10,000 miles. For me this is 4 oil changes a year. I cleaned it out just by switching oils. The oil ports were clogged up (causing overheating) with buildup from PTFE (teflon) additives in previous oils. Never again.
Last edited by rcissna; 07-05-2008 at 11:39 AM.