Simply put, engine sludge is the thick, dark substance that can build up and clog the oil passages within an engine. Sludge build-up can lead to reduced gas mileage, decreased engine performance and, in some cases, engine seizure.

Learn how you can help prevent Sludge build up with CastrolGTX

What are some of the causes of engine sludge?

You may be surprised at what you find out!