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 pack. The package includes two 5-quart bottles and spans several common viscosity grades. Along with this price hike, Costco has imposed a purchase cap on the item. Members are restricted to buying no more than two units in a single transaction within a seven-day window. This limit is visible on select Kirkland Signature motor oil listings on the company’s website.
This new price point represents a significant rise from the figures observed roughly a year prior, when the same volume was sold for around $30. Currently, Costco offers multiple Kirkland full synthetic options online at $57.99, including 5W-30, 5W-20, and 0W-20 formulations. It’s worth noting that in-store prices can differ from those online and may vary depending on location. Each package provides 10 quarts of oil, making this change particularly notable for consumers purchasing oil for regular vehicle maintenance routines.
The purchase restrictions extend beyond Kirkland products to include several Mobil 1 offerings available through Costco. Mobil 1, a brand owned by ExxonMobil, is among the most recognized synthetic motor oil brands across the United States. Currently, six-packs of one-quart bottles are limited to a maximum of five units per member. These affected listings encompass both standard and high-mileage formulations across various viscosity grades. Consequently, the purchase limits are not exclusive to Costco’s private-label oils but also include a major national lubricant brand.
Limits on Purchases Extend Beyond Kirkland Oil
The production of synthetic motor oils relies heavily on refined base oils and additives that meet contemporary engine protection standards. Among these, Group III base oils play a crucial role in many synthetic lubricant formulations. The United States depends on international suppliers for a significant portion of these materials. A large share of global Group III output is supplied by producers in the Persian Gulf. Recent disruptions in Middle Eastern energy markets have resulted in tighter supplies of various petroleum products and refining components used across the lubricant industry, impacting availability.
Meanwhile, crude oil prices remained above $100 per barrel into mid-September. On September 16, Brent crude was trading near $107.82, while West Texas Intermediate hovered around $104.86. These market conditions continue to reflect ongoing disruptions affecting major Middle East production and shipping channels. Transit through the Strait of Hormuz remains significantly below typical levels, and infrastructure in Saudi Arabia’s Red Sea export terminals has experienced interruptions, further putting pressure on regional petroleum supplies.
The Broader Impacts on Synthetic Oil Supply Chains
Costco’s range of affected Kirkland oils includes grades suitable for many passenger cars, SUVs, and light trucks. The retailer emphasizes that these oils protect against engine wear and help manage thermal breakdown. Several formulations meet API SP and ILSAC GF-6A standards, which address engine cleanliness, fuel efficiency, and wear protection. Additionally, the Mobil 1 products available at Costco cover standard, fuel-economy, and high-mileage options, all subject to the new purchase limits.
The company has not issued a detailed public statement explaining the reasons behind the increased prices for Kirkland motor oil or the introduction of purchase caps. As of now, online listings display both the $57.99 price tag and the two-unit purchase restriction for selected items. Meanwhile, separate Mobil 1 product pages continue to show a five-unit limit per membership for several formulations. These changes come amid high crude prices and tightening lubricant supplies, with Costco’s posted restrictions providing members with clarity on product availability and purchasing rules.