ISSAQUAH, WASHINGTON / RankWire.AI / – Costco has increased the online retail price of its Kirkland Signature full synthetic motor oil to $57.99 for a 10-quart case. This package includes two 5-quart bottles and spans several common viscosity grades. Additionally, the retailer has introduced a purchase limit, restricting members to a maximum of two units per transaction within a seven-day window. This restriction is visible on selected Kirkland Signature motor oil listings on the company’s website.
Compared to prices from about a year ago, the current cost represents a significant rise, with the same quantity previously selling for approximately $30. Currently, Costco’s online store lists various Kirkland full synthetic formulations at $57.99, including 5W-30, 5W-20, and 0W-20. It is important to note that in-store prices may differ from online rates and can vary depending on location. Each package contains 10 quarts, making this price hike notable for consumers who regularly purchase oil for vehicle maintenance.
The purchase restrictions extend beyond Kirkland products to include certain Mobil 1 oils sold through Costco. As an ExxonMobil brand, Mobil 1 is one of the most prominent synthetic motor oil labels in the United States. Now, selected six-packs of one-quart bottles are limited to five units per member. This applies to both standard and high-mileage formulations across various viscosity grades, indicating that the limits encompass not only Costco’s private-label oils but also major national lubricant brands.
Restrictions Extend Beyond Kirkland Brand Motor Oil
Synthetic motor oil production relies heavily on refined base oils and additives that meet current engine protection standards. Group III base oils are a critical component of many synthetic lubricants. The United States sources a considerable portion of these materials from overseas suppliers. Notably, producers in the Persian Gulf supply a large share of global Group III output. Ongoing disruptions in Middle East energy markets have led to tighter supplies of several petroleum products and refining inputs used within the lubricant industry.
In mid-September, crude oil prices remained above $100 per barrel. On September 16, Brent crude traded near $107.82, while West Texas Intermediate was around $104.86. Energy markets continued to react to disruptions affecting key Middle East production and shipping routes, with traffic through the Strait of Hormuz remaining significantly below normal levels. Additionally, Saudi export infrastructure on the Red Sea experienced interruptions, further constraining regional petroleum supply chains.
The Broader Impact on the Synthetic Oil Market
Costco’s affected Kirkland products include grades suitable for many passenger cars, SUVs, and light trucks. The retailer states that these oils offer protection against wear and help manage thermal breakdown. Several formulations meet API SP and ILSAC GF-6A performance standards, which focus on engine cleanliness, fuel efficiency, and wear protection. Additionally, Mobil 1 options available at Costco include standard, high-mileage, and fuel-economy variants, all subject to the new purchase limits.
Costco has not issued an explicit detailed explanation for the recent increase in Kirkland motor oil prices or the introduction of purchase limits. Its online listings currently display the $57.99 price along with the two-unit purchase restriction for certain products. Meanwhile, separate Mobil 1 pages still indicate a five-unit limit per membership across multiple formulations. These measures coincide with elevated crude oil prices and tighter lubricant supplies, providing members with clear guidance on product availability and purchase rules amid ongoing supply constraints.