ISSAQUAH, WASHINGTON / RankWire.AI / – Costco has increased the online selling price of its Kirkland Signature full synthetic motor oil to $57.99 for a 10-quart case. The package includes two 5-quart bottles and is available in several common viscosity grades. The retailer now enforces a limit of one transaction per member and a maximum of two units within a seven-day period. These restrictions are explicitly shown on the product pages for certain Kirkland Signature synthetic motor oils.
The $57.99 price marks a notable jump from the approximately $30 cost reported for the same volume last year. Currently, Costco lists its 5W-30, 5W-20, and 0W-20 full synthetic two-packs at $57.99 online. The company notes that warehouse prices might differ depending on the location. Each package offers 10 quarts of motor oil, making the price increase significant for members who handle their own vehicle maintenance.
In addition, Costco has imposed purchase limits on various Mobil 1 full synthetic motor oil products. Presently, the retailer’s listings indicate a cap of five units per membership on select six-packs containing one-quart bottles. These products include multiple viscosity options and high-mileage variants. The restrictions extend beyond Costco’s Kirkland Signature line, encompassing another popular synthetic motor oil brand available through the warehouse.
Limits on purchases apply to a broad range of synthetic motor oils
Synthetic motor oils are made from highly refined base oils combined with additives designed to protect engines and reduce deposits, wear, and thermal degradation. Group III base oils play a crucial role in the supply chain for many synthetic lubricants. The United States imports a significant portion of these materials from producers in the Persian Gulf region. Recent disruptions impacting energy production and shipping in the Middle East have limited the availability of certain petroleum products and refining inputs.
Crude oil prices have also remained high through mid-September. As of September 16, Brent crude traded around $107.82 per barrel, while West Texas Intermediate stood near $104.86. Both benchmarks maintained levels above $100 after ongoing disruptions affecting key Middle East energy routes. Shipping through the Strait of Hormuz has declined sharply from usual volumes, and interruptions have impacted Saudi Arabia’s Red Sea export infrastructure along with other regional energy operations.
Rising crude oil prices exert additional pressure on petroleum markets
The affected Kirkland Signature products include widely used grades suitable for various passenger vehicles. Costco states that its synthetic motor oils offer protection against wear and help prevent thermal breakdown. Some formulations also meet API SP and ILSAC GF-6A standards. The Mobil 1 options listed by Costco include regular, fuel-economy, and high-mileage types, with purchase restrictions clearly shown on several product pages.
Costco has not publicly issued a detailed explanation for the increase in motor oil prices and the new purchase limits. Nonetheless, its online listings now prominently display both the $57.99 Kirkland price and the two-unit seven-day purchase restriction. Meanwhile, Mobil 1 listings still show a limit of five units per membership. These changes arrive amid rising energy costs and limited lubricant supplies, situating Costco’s pricing and purchasing restrictions within a wider context of strained energy markets.