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 case, which contains two 5-quart bottles in several common viscosity grades. The retailer has also introduced a purchase limit on certain Kirkland motor oil products, restricting members to buy no more than two units in a single transaction within a seven-day window, according to Costco’s current online listings.
This new $57.99 price is almost double the roughly $30 reported for the same quantity last year. Costco lists Kirkland 5W-30, 5W-20, and 0W-20 full synthetic oils at this higher online rate, though prices at warehouse stores may vary from those displayed online. The price hike impacts customers purchasing larger quantities for routine vehicle maintenance, as each Kirkland package contains 10 quarts of synthetic oil.
Additionally, Costco has set purchase limits on select Mobil 1 synthetic motor oils. Mobil 1, an ExxonMobil brand, appears in several Costco listings with a cap of five units per membership. These include six-packs of one-quart bottles across multiple viscosity grades, with some listings featuring standard formulations and others high-mileage variants. The restrictions therefore apply not only to Costco’s private-label Kirkland motor oils but also to certain Mobil 1 products from a major national lubricant supplier.
Restrictions Go Beyond Kirkland Oils
Manufacturing synthetic motor oils depends on refined base oils and additives designed to shield engines from heat and heavy-duty operation. Group III base oils are a key component in many synthetic lubricants sold in the United States. A substantial portion of these supplies are imported by American buyers from overseas producers, including facilities in the Persian Gulf. Recent disruptions in Middle East energy markets have led to reduced availability of some petroleum products and tightened parts of the lubricant supply chain.
In mid-September, crude oil prices stayed above $100 per barrel. On September 16, Brent crude traded near $107.82, with West Texas Intermediate close to $104.86. Ongoing Middle Eastern supply disruptions continue to influence production, exports, and shipping routes, with traffic through the Strait of Hormuz remaining below normal levels. Saudi Arabia’s Red Sea energy infrastructure also faced disruptions, adding to pressures across petroleum markets and the broader network supplying refined products and lubricants.
Rising Oil Prices Tighten Lubricant Supplies
The impacted Kirkland motor oils are used in many passenger cars, SUVs, and light trucks. Costco emphasizes that its full synthetic oils help prevent engine wear and thermal breakdown, with some products meeting API SP and ILSAC GF-6A standards for modern gasoline engines. The API manages motor oil standards in the United States, while ILSAC specifications address fuel economy, engine cleanliness, and wear protection, which are listed on several Kirkland synthetic oil items.
Costco has not provided an official detailed explanation for the price increase or the new purchase limits on Kirkland motor oils. Currently, its website displays the $57.99 price along with a restriction of two units per week on selected Kirkland products. Meanwhile, separate Mobil 1 listings continue to impose a five-unit limit per membership on multiple formulations. These changes come amid elevated crude oil prices and tighter lubricant supplies, with Costco’s posted limits now defining how much members can buy through affected online listings.
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