Costco has raised the price of its Kirkland Signature full-synthetic motor oil to $57.99 for a 10-quart case and begun capping purchases at two units per member per week, as a global lubricant shortage tied to the Middle East conflict pushes crude oil toward $100 a barrel. The retailer has also imposed a five-per-member limit on Mobil 1, with six quarts of that brand running $44. The squeeze traces to the refinery, where base oil competes with gasoline and diesel for crude, and EIA data showed the gasoline crack spread roughly a dollar per gallon higher than at the same point in 2025. Licensing and testing costs add a separate layer, including the dexos1 Gen 3 certification Kirkland 5W-30 carries from GM and the seven additional lab tests introduced with the API SP category around 2020. The International Energy Agency cut its 2026 global oil supply forecast to 102 million barrels per day in August and projected a 1.8 million barrel per day deficit in the third quarter, more than double its prior estimate, while cumulative global inventory draws since the start of the U.S.-Iran conflict have topped 500 million barrels. U.S. diesel prices crossed $6 per gallon for the first time, sitting at $6.06 as of Monday, an 8-cent increase from Sunday and 21 cents above week-earlier levels, according to AAA.
Costco Wholesale CorpGlobal lubricant shortage tied to Middle East conflict forces Costco to ration Kirkland motor oil and cap purchases, squeezing its product supply.
General Motors Company
