ISSAQUAH, WASHINGTON / RankWire.AI / – Costco has increased the online cost of its Kirkland Signature full synthetic motor oil to $57.99 for a 10-quart case. Each case includes two 5-quart bottles in a variety of common viscosity grades. The retailer has also set purchase restrictions on certain Kirkland motor oil products. According to Costco’s current online listings, members are limited to buying a maximum of two units within one transaction over a seven-day span.
The new price of $57.99 is nearly double the roughly $30 reported for the same quantity last year. Costco lists Kirkland full synthetic oils, such as 5W-30, 5W-20, and 0W-20, at this elevated online rate. Prices at warehouse stores might differ from those displayed on the company’s website. This change primarily impacts customers purchasing larger quantities for routine vehicle maintenance, as each Kirkland package contains 10 quarts of synthetic oil.
Additionally, Costco has imposed purchase limits on select Mobil 1 synthetic motor oils. Mobil 1, a brand owned by ExxonMobil, appears in several Costco listings with a cap of five units per membership. These products include six-packs of one-quart bottles across multiple viscosity grades. Some listings feature standard formulations, while others include high-mileage options. As a result, restrictions apply not only to Costco’s private-label Kirkland oils but also to certain Mobil 1 products from a major national lubricant brand.
Restrictions on motor oil extend beyond Kirkland offerings
Synthetic motor oils depend on refined base oils combined with additives engineered to safeguard engines under heat and heavy usage. 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 from overseas producers, including facilities in the Persian Gulf. Recent disruptions in Middle East energy markets have led to reduced availability of certain petroleum products and tightened parts of the lubricant supply chain.
Crude oil prices remained above $100 per barrel in mid-September. On September 16, Brent crude was trading near $107.82, while West Texas Intermediate was around $104.86. Ongoing disruptions in Middle Eastern supply chains continued to impact production, exports, and shipping routes, including traffic through the Strait of Hormuz, which remained below typical levels. Saudi Arabia’s Red Sea energy infrastructure also faced interruptions, adding further pressure to petroleum markets and the broader network supplying refined products and lubricants.
Rising crude oil prices correlate with tighter lubricant inventories
The affected Kirkland motor oils cater to a wide range of passenger cars, SUVs, and light trucks. Costco emphasizes that its full synthetic oils are designed to protect engines from wear and thermal degradation. Several products meet API SP and ILSAC GF-6A standards, which are required for modern gasoline engines. The American Petroleum Institute sets the API standards, while ILSAC specifications address fuel economy, engine cleanliness, and wear protection. These standards are displayed on multiple Kirkland synthetic oil listings.
Costco has not provided a detailed public explanation for the price hike or the new purchase restrictions on Kirkland motor oils. Currently, the website shows the $57.99 price and the two-unit, seven-day limit for selected products. Meanwhile, separate Mobil 1 listings continue to enforce a five-unit limit per membership on various formulations. These changes occur amid elevated crude oil prices and a constrained lubricant supply, with the new limits guiding members on the maximum quantities they can purchase online for affected items.