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 pack, which contains two 5-quart bottles and is available in various common viscosity grades. Members are now limited to one purchase per transaction and a maximum of two units within seven days, with these restrictions clearly displayed on product pages for selected Kirkland Signature synthetic motor oils.
This $57.99 cost marks a significant jump from the approximately $30 price for the same quantity reported last year. Currently, Costco lists its 5W-30, 5W-20, and 0W-20 full synthetic two-packs at this price online, although the retailer notes that warehouse prices may vary by location. Each package offers 10 quarts of motor oil, making the increase notable for members who handle their vehicle maintenance themselves.
In addition to Kirkland Signature, Costco has imposed purchase limits on several Mobil 1 full synthetic motor oil products. Listings now show a restriction of five units per membership for certain six-packs containing one-quart bottles, including various viscosity options and high-mileage formulations. These restrictions extend beyond Kirkland Signature products to also include other popular synthetic motor oils sold at Costco.
Limits cover multiple synthetic motor oil brands
Synthetic motor oils combine highly refined base oils with additives designed to protect engines and prevent deposits, wear, and thermal breakdown. Group III base oils are a key component of many synthetic lubricants, and the United States imports a significant portion of these materials from producers across the Persian Gulf. Recent disruptions in energy production and shipping in the Middle East have tightened the supply of certain petroleum products and refining inputs.
Meanwhile, crude oil prices remain elevated in mid-September, with Brent crude trading near $107.82 per barrel on September 16, and West Texas Intermediate close to $104.86. Both benchmarks have remained above $100 after weeks of disruptions impacting major Middle East energy routes. Shipping through the Strait of Hormuz has dropped sharply from normal levels, and regional energy operations—including Saudi Arabia’s Red Sea export infrastructure—have experienced disruptions.
Rising crude prices influence petroleum markets broadly
The affected Kirkland Signature products include widely used grades suitable for a variety of passenger vehicles, with Costco stating that its synthetic oils offer wear protection and help prevent thermal breakdown. Several formulations meet API SP and ILSAC GF-6A performance standards. Among the Mobil 1 options listed by Costco are standard, fuel-economy, and high-mileage formulas, with purchase limits clearly shown on multiple product pages.
While Costco has not offered an official explanation for the price hike and purchase restrictions, its online listings now prominently display the $57.99 Kirkland price along with the two-unit seven-day cap. Meanwhile, Mobil 1 products still show a limit of five units per membership. These adjustments come amid rising petroleum prices and tighter lubricant supplies, placing Costco’s pricing policies and purchase restrictions within a broader context of strained energy markets.