Popular Synthetic Oil Brands Ranked Worst To Best – SlashGear

Castrol is a London-based company that got its start back in 1899 when it made the discovery that the addition of castor oil to lubricants designed for airplanes and automobiles thinned the mixture enough to allow it to work from cold starts while still maintaining viscosity at high operating temperatures.

Castrol’s focus — at least in its marketing — is on making a motor oil that’s designed primarily to fight the buildup of sludge in an engine. To that end, its GTX Full Synthetic is reportedly better at protecting against the buildup of sludge in engines when compared to the API’s standard. In addition, GTX also provides wear protection six times better than that standard. Further, the Edge line of synthetics boasts the ability to maintain engine protection for 10,000 miles while also being a carbon-neutral product.

Amazon reviews for the product reveal a 4.8 star average, although only a little over 3,500 reviewers have left a rating -– far less than the last few entries on our rankings, but enough to show the loyalty from the Castrol crowd. That isn’t limited to just customers, as Castrol Edge is the OEM partner of several of the world’s largest automakers, including Honda, Volvo, Land Rover, Jaguar, Subaru, Ford, and Renault–Nissan–Mitsubishi.