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. Each case includes two 5-quart bottles across several common viscosity grades. Additionally, the retailer has implemented a purchase restriction on certain Kirkland motor oil items. Members are limited to buying a maximum of two units per transaction within a seven-day window, according to Costco’s current online listings.
The new price of $57.99 is nearly double the approximately $30 that was reported for the same quantity last year. Costco currently lists Kirkland 5W-30, 5W-20, and 0W-20 full synthetic oils at this higher online rate. Prices at warehouse locations may vary from those displayed on the website. This change primarily impacts customers purchasing larger quantities for regular vehicle maintenance, as each Kirkland package contains 10 quarts of synthetic motor oil.
Costco has also set purchase limits on selected Mobil 1 synthetic motor oil products. Mobil 1, a brand owned by ExxonMobil, appears in several Costco listings with a cap of five units per membership. These include six-packs of one-quart bottles in different viscosity grades. Some listings feature standard formulations, while others include high-mileage variants. The restrictions therefore apply to both Costco’s private-label Kirkland motor oil and certain products from a major national lubricant brand.
Restrictions on motor oil purchases go beyond Kirkland items
Synthetic motor oils depend on refined base oils and additives designed to safeguard engines under heat and heavy use. Many such lubricants sold in the United States contain Group III base oils. A significant portion of these supplies are imported by American consumers from overseas producers, including facilities in the Persian Gulf. Recent disruptions in Middle East energy markets have reduced the availability of certain petroleum products and have 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, while West Texas Intermediate was close to $104.86. Ongoing disruptions in Middle East supply chains continue to influence production, exports, and shipping routes. Traffic through the Strait of Hormuz remains below typical levels. Interruptions have also affected Saudi Arabia’s Red Sea energy infrastructure, adding pressure to petroleum markets and the broader network that supplies refined products and lubricants.
Rising crude oil prices are coupled with tightening lubricant supplies
The affected Kirkland motor oils serve a wide range of passenger cars, SUVs, and light trucks. Costco states that its full synthetic oils help shield engines from wear and thermal breakdown. Some products meet API SP and ILSAC GF-6A standards, which are designed for modern gasoline engines. The American Petroleum Institute oversees API motor oil standards, while ILSAC specifications address aspects like fuel economy, engine cleanliness, and wear protection. Several Kirkland synthetic oil listings display these standards.
Costco has not provided a detailed public explanation for the price hike of Kirkland motor oils or the new purchase limits. Its website currently shows the $57.99 price and a restriction of two units within seven days on selected products. Meanwhile, separate Mobil 1 listings still display a five-unit per membership limit across various formulations. These changes come amid rising crude prices and constrained lubricant supplies, with Costco’s posted limits now defining how much members can purchase online for affected products.