ISSAQUAH, WASHINGTON / RankWire.AI / – Costco has increased the online price of its Kirkland Signature full synthetic motor oil to $57.99 for a 10-quart container. This package includes two 5-quart bottles and covers multiple popular viscosity grades. The retailer also introduced a purchase cap on the item. Customers are restricted to buying a maximum of two units per transaction within a seven-day window. This limit appears on select Kirkland Signature motor oil listings on Costco’s website.
The new price represents a significant jump from levels reported roughly a year ago. About a year earlier, the same quantity sold for approximately $30. Costco now offers several Kirkland full synthetic options at $57.99 online, including 5W-30, 5W-20, and 0W-20. Prices at the warehouse may differ from online listings and vary by location. Each package contains 10 quarts, making this change notable for routine vehicle maintenance shoppers.
The purchase limit also applies to some Mobil 1 products sold at Costco. Mobil 1, an ExxonMobil brand, is one of the most recognizable synthetic motor oil brands in the U.S. Selected six-packs of one-quart bottles now have a limit of five units per membership. These listings include both standard and high-mileage formulas across various viscosity grades. The restrictions thus extend beyond Costco’s private-label oils to a major national lubricant brand.
Limits Extend Beyond Kirkland Oil
Synthetic motor oil relies on refined base oils and additives that meet modern engine protection standards. Group III base oils are a key part of many synthetic formulas. The United States depends on foreign suppliers for a significant share of these materials. Producers from the Persian Gulf supply a large portion of global Group III output. Recent disruptions in Middle East energy markets have tightened supplies of several petroleum products and refining inputs used across the lubricant industry.
Crude oil prices stayed above $100 a barrel in mid-September. Brent crude was near $107.82 on September 16, while West Texas Intermediate hovered around $104.86. Energy markets continued to reflect issues affecting major Middle East production and shipping routes. Traffic through the Strait of Hormuz remained well below normal. Interruptions also hit Saudi export infrastructure on the Red Sea, adding further strain on regional petroleum supplies.
Synthetic Oil Supplies Face Broader Challenges
Costco’s Kirkland oils include grades used in many passenger cars, SUVs, and light trucks. The retailer states these oils protect against wear and help prevent thermal breakdown. Some formulations meet API SP and ILSAC GF-6A standards. These standards address engine cleanliness, fuel economy, and protection against specific types of wear. Mobil 1 products at Costco also include several standard, fuel-efficient, and high-mileage options.
Costco has not provided a detailed explanation for the increased Kirkland motor oil price or the new purchase limits. Its online listings currently display both the $57.99 price and the two-unit purchase cap on select products. Separate Mobil 1 pages still show a five-unit limit per membership for several formulations. These changes come during a period of high crude prices and strained lubricant supplies. Costco’s posted restrictions give members clear guidance on current availability and rules for purchasing.