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. Each container holds two 5-quart bottles across various common viscosity grades. The retailer has also set purchase limits on certain Kirkland motor oil items. Members can buy no more than two units per transaction within a seven-day window, according to Costco’s current online listings.
This new $57.99 cost is nearly double the approximate $30 price reported last year for the same quantity. Costco lists Kirkland 5W-30, 5W-20, and 0W-20 full synthetic oils at this increased online rate. Actual prices at warehouse stores might differ from those on the website. The change primarily impacts customers purchasing larger amounts for routine vehicle maintenance, as each Kirkland package contains 10 quarts of synthetic oil.
In addition, Costco has imposed limits on select Mobil 1 synthetic motor oil products. An ExxonMobil brand, Mobil 1 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 are high-mileage variants. Restrictions thus apply to both Costco’s private-label Kirkland oil and certain Mobil 1 products from a major national brand.
Restrictions on motor oil extend beyond Kirkland offerings
Synthetic motor oils depend on refined base oils and additives designed to withstand engine heat and heavy use. Group III base oils are a key component in many synthetic lubricants sold in the United States. A significant portion of these supplies is imported from overseas producers, including facilities in the Persian Gulf. Recent disruptions in Middle East energy markets have reduced the availability of some petroleum products and tightened parts of the lubricant supply chain.
Crude oil prices remained above $100 per barrel into mid-September. Brent crude traded close to $107.82 on September 16, while West Texas Intermediate hovered around $104.86. Ongoing Middle East supply interruptions affected 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 experienced disruptions, adding further strain on petroleum markets and the broader supply chain for refined products and lubricants.
Rising crude oil costs tighten lubricant supply chains
Costco’s affected Kirkland oils serve a range of passenger cars, SUVs, and light trucks. The retailer claims its full synthetic oils help prevent engine wear and thermal breakdown. Several products meet API SP and ILSAC GF-6A standards, which ensure performance for modern gasoline engines. The API standards are managed by the American Petroleum Institute, while ILSAC standards address fuel economy, engine cleanliness, and wear protection. These standards are visible on multiple Kirkland synthetic oil listings.
Costco has not provided a detailed public explanation for the price hike or the new purchase limits. Its website currently displays the $57.99 price alongside a two-unit seven-day purchase restriction on selected Kirkland products. Meanwhile, Mobil 1 listings still show a five-unit limit per membership. These adjustments occur amid rising crude oil prices and tighter lubricant supplies, with Costco’s posted limits now dictating how much members can buy through online listings.