Costco has increased the price of its Kirkland Signature full-synthetic motor oil to $57.99 and is limiting purchases to two units per member per week. This change comes as a global lubricant shortage, linked to the ongoing conflict in the Middle East, drives crude oil prices toward $100 per barrel. Previously, the price for this 10-quart case was approximately $30. Additionally, Costco has set a five-unit limit on Mobil 1 oil, which is priced at $44 for six quarts.
The price increase and rationing are influenced by several factors, including the relationship between fuel prices and lubricant production. According to The Auto Wire, when margins for finished fuel are high, refiners tend to prioritize fuel production over lubricants. Recent data from the Energy Information Administration (EIA) indicates that the gasoline crack spread is about a dollar per gallon higher than it was at the same time in 2025, affecting the availability and price of base oil.
Regulatory and licensing costs also contribute to the increased price. The Kirkland 5W-30 oil meets GM's dexos1 Gen 3 certification, which requires manufacturers to undergo independent testing and pay licensing fees for each product. Furthermore, the introduction of the API SP category in 2020 added seven new laboratory tests, increasing production costs.
The current supply challenges occur amid a worsening global oil deficit. The International Energy Agency (IEA) revised its 2026 global oil supply forecast to 102 million barrels per day in August, predicting a deficit of 1.8 million barrels per day in the third quarter, more than double its previous estimate. Since the onset of the U.S.-Iran conflict, global inventory draws have exceeded 500 million barrels. As of Monday, U.S. diesel prices reached $6.06 per gallon, an increase of 8 cents from the previous day and 21 cents from the prior week, according to AAA.
For consumers who perform their own oil changes, the cost-effectiveness of this option has diminished, as the price of Kirkland oil now aligns closely with the charges of local independent shops, according to The Auto Wire.