ISSAQUAH, WASHINGTON / RankWire.AI / – Costco has increased the online retail price of its Kirkland Signature full synthetic motor oil to $57.99 per 10-quart case. Each case contains two 5-quart bottles across several common viscosity grades. Additionally, the retailer has introduced a purchase cap on selected Kirkland motor oil items. According to Costco’s current online listings, members are restricted to buying a maximum of two units per transaction within a seven-day window.
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 full synthetic oils in 5W-30, 5W-20, and 0W-20 viscosities at this higher online rate. Prices at physical warehouse locations may differ from those displayed online. This change particularly impacts customers purchasing larger quantities for routine vehicle maintenance, considering each Kirkland package contains 10 quarts of synthetic motor oil.
Furthermore, Costco has imposed restrictions on specific Mobil 1 synthetic motor oil products. Mobil 1, a brand owned by ExxonMobil, is featured in several Costco listings with a limit of five units per membership. These include six-packs of one-quart bottles in various viscosity grades. Some listings feature standard formulations, while others are high-mileage variants. Consequently, these purchase limits apply not only to Costco’s private-label Kirkland oils but also to selected products from a major national lubricant brand.
Restrictions on motor oil extend beyond Kirkland offerings
The production of synthetic motor oils depends on refined base oils and additives engineered to safeguard engines under high heat and heavy-duty operation. Group III base oils play a key role in many synthetic lubricants available in the United States. American consumers import a significant portion of these supplies from overseas manufacturers, including facilities situated in the Persian Gulf. Recent disturbances within Middle East energy markets have caused a reduction in the availability of certain petroleum products and have tightened the supply chain for lubricants.
As of mid-September, crude oil prices remained above $100 a barrel. On September 16, Brent crude traded close to $107.82, whereas West Texas Intermediate hovered around $104.86. Ongoing disruptions in Middle Eastern supply chains continued to influence production, export routes, and shipping lanes. Traffic through the Strait of Hormuz remained below normal, while interruptions affected Saudi Arabia’s Red Sea energy infrastructure, adding further pressure on petroleum markets and the broader network that supplies refined products and lubricants.
Rising crude oil prices exacerbate lubricant supply constraints
The affected Kirkland synthetic oils are suitable for many passenger vehicles, SUVs, and light trucks. According to Costco, their full synthetic products assist in protecting engines from wear and thermal deterioration. Selected formulations meet API SP and ILSAC GF-6A standards for modern gasoline engines. Managed by the American Petroleum Institute, these standards cover aspects like fuel efficiency, engine cleanliness, and wear protection. Several Kirkland synthetic oil listings display these certifications.
Costco has yet to provide a detailed public statement explaining the reasons behind the increase in Kirkland motor oil prices or the new purchase restrictions. Presently, its website lists the $57.99 price along with a two-unit, seven-day limit on certain Kirkland products. Meanwhile, separate listings for Mobil 1 continue to feature a five-unit per membership limit across several formulations. The timing of these adjustments coincides with heightened crude oil prices and tighter lubricant supplies, with Costco’s posted restrictions now defining the maximum quantities members can buy online from affected listings.