Extended drain intervals involve changing the frequency of oil changes from the what the manufacturer recommends to a longer interval. The first thing most people ask is if it is safe. Depending on the oil you use it can be safe and as long as the oil conforms to the American Petroleum Institute (API) standards required by the manufacturer and is providing that level of protection, manufacturers cannot deny warranty claims.
FTC regulations state: (c) No warrantor of a consumer product may condition his written or implied warranty of such product on the consumers using, in connection with such product, any article or service (other than article or service provided without charge under the terms of the warranty) which is identified by brand, trade, or corporate name; except that the prohibition of this subsection may be waived by the Commission if (1) the warrantor satisfies the Commission that the warranted product will function properly only if the article or service so identified is used in connection with the warranted product, and (2) the Commission finds that such a waiver is in the public interest. (15 U.S.C.2302(C))
When choosing a motor oil for extended drain intervals, you need to look at how they perform in industry standard tests that demonstrate how well they perform. Synthetic oils typically provide better protection because they are made with a base stock of uniformly size molecules that have a higher lubricity than conventional petroleum where base stocks contain various size molecules. The four ball wear test (ASTM D-4172) is one such example where three metal balls are strapped together with a coating of the lubricant then a fourth ball is rotated over the others for an hour using 40 kg of force at a temperature of 150 C. The resulting scar is measured and the narrower the scar, the better protection. Another factor to consider is the Total Base Number (TBN) test which measures the alkalinity of an oil. This is important, especially in extended drain scenarios, because it measures the oil ability to counteract the acidity that builds up in the crankcase and corrodes engine parts.
Filters are also an important consideration and you need to make sure that you are using a filter designed to provide service for the extended drain interval. Alternatively, you could change the filter between oil changes following the filter manufacturer’s recommendation.
Extended drain intervals save you money by consuming less oil and filters and time in maintenance of the equipment. It’s also better for the environment by producing less waste of containers and consuming less resources. And if you use a quality product, you can give your equipment better protection at the same time.
There are other tests and if you are interested in learning more please contact me, Steve Schoeneman, at email@example.com or 360-450-4445. I’ve been using AMSOIL and 25,000 mile drain intervals for over 7 years with over 197,000 miles on my 1997 Jeep Wrangler with no problems.