Costco members who rely on Kirkland Signature synthetic motor oil for DIY car maintenance are facing new challenges as prices rise and purchase limits are introduced. A 10-quart case of Kirkland full-synthetic motor oil now costs $57.99, a significant increase from the mid-$30 range it maintained for years. Additionally, Costco has restricted purchases to two units per member every seven days, capping the maximum at 20 quarts during that period.
Motor oil rationing is uncommon and signals notable supply issues. The tightening supply is partly due to the more complex and costly process of producing modern lubricants that meet stringent engine requirements. Today's oils must support advanced engine technologies such as turbochargers and direct injection, while complying with rigorous industry standards like General Motors’ dexos1 Gen 3 and API/ILSAC certifications. These standards require extensive testing to ensure protection against issues like low-speed pre-ignition.
The base oils used in lubricants come from the same refining processes as gasoline and diesel. When fuel markets offer higher returns, refiners may prioritize fuel production, reducing lubricant base-stock availability. This upstream pressure contributes to higher costs that eventually impact retail prices.
Costco's purchase limits extend beyond Kirkland products; Mobil 1 motor oil is also rationed, though with a higher limit of five units per member. For consumers who perform their own oil changes, these developments mean increased expenses and reduced availability. The combination of price hikes and rationing underscores the current strain on the motor oil supply chain and the evolving challenges in lubricant production.