Costco has started rationing its motor oil, putting a two-box-per-customer weekly limit on its 10-quart Kirkland Signature full-synthetic oil while raising the price of the same box from $30 to $58. That is a 93% increase, and it lands on shoppers who have long expected Costco to sell in bulk, not ration like a refinery under strain.
The move matters now because drivers who handle their own oil changes are already facing tighter supply and higher prices across the market. A six-quart case of Mobil 1 is priced at $44, and Costco has capped purchases of Mobil 1 at five per member, signaling that the limits are not a one-off but part of a broader squeeze on motor oil sales.
The pressure reaches beyond a warehouse shelf. The shortage is rooted in international conflict, and the United States imports nearly 44% of its Group III supply directly from Bapco in Bahrain, ADNOC in the United Arab Emirates and Pearl GTL in Qatar. Synthetic motor oil depends heavily on Group III base oils, so when that supply chain tightens, the retail market feels it quickly.
The disruption has deepened since March 2026, when the Pearl GTL facility in Qatar sustained heavy damage from Iranian airstrikes. The source says that damage crippled a major portion of global production for at least a year, while the ongoing military entanglement with Iran and the blockade of the Strait of Hormuz have choked off exports. At the same time, South Korean refiners are struggling to secure raw crude oil, and diesel and jet fuel margins have climbed to 40-year highs, pulling feedstock toward the most profitable uses.
That is the friction in Costco’s response: a company built on bulk sales is now telling members to buy less of a basic maintenance item. General Motors also requires vendors to pay double licensing fees to print the Dexos-approved badge on packaging, and that certification appears on Costco’s Kirkland brand, making the oil more complex and more expensive to put on shelves. Costco has not said how long the weekly limit will stay in place, and that unanswered detail is what shoppers will be watching next.
