Various environmental factors, such as subpar fuel quality, hot weather, and stop-start driving conditions, can have detrimental effects on your engine. The accumulation of sludge, varnish, and carbon build-up due to these factors can significantly reduce engine life, power output, and fuel economy. Castrol Ultraclean is a synthetic blend engine oil available in 0W-20, 5W-20, and 5W-30 grades. Its unique double-action formula has been scientifically proven to effectively cleanse and remove sludge that can obstruct vital engine oilways*. Additionally, its advanced synthetic technology aids in preventing the formation of new sludge. In fact, it offers up to 1.4 times superior sludge protection compared to the latest industry standard. When it comes to maintaining a clean engine, no other oil can rival the performance of Castrol Ultraclean.