Evaluation of Elastomeric Compounds in “Fresh” and “Used” CG-4 Engine Oils

Engine oils and their environment can have a negative effect on some elastomeric materials. This depends on the brand of the engine oil and how properties of the oil change between drain intervals. Some elastomeric materials perform poorly in unaged engine oils but well in the aged or ‘used’ oils. Others perform poorly in the ‘used’ fluid but well in the unaged oils, and other elastomeric materials are insensitive to the brand of oil or its age.