ISSAQUAH, WASHINGTON / RankWire.AI / – Costco has raised the online price of its Kirkland Signature full synthetic motor oil to $57.99 for a 10-quart case. The package contains two 5-quart bottles and comes in several common viscosity grades. Costco now limits members to one transaction and a maximum of two units every seven days. The restrictions appear directly on the retailer’s product pages for selected Kirkland Signature synthetic motor oils.
The $57.99 price represents a sharp increase from the roughly $30 level reported for the same quantity last year. Costco currently lists its 5W-30, 5W-20 and 0W-20 full synthetic two-packs at $57.99 online. The retailer notes that warehouse prices can vary by location. Each package provides 10 quarts of motor oil, making the price change significant for members who perform their own vehicle maintenance.
Costco has also placed purchase limits on several Mobil 1 full synthetic motor oil products. Current Costco listings show a limit of five units per membership on selected six-packs containing one-quart bottles. Those products include several viscosity and high-mileage formulations. The restrictions broaden the change beyond Costco’s Kirkland Signature label and cover another widely sold synthetic motor oil brand available through the warehouse retailer.
Purchase limits extend across synthetic motor oil listings
Synthetic motor oils use highly refined base oils combined with additives that protect engines and control deposits, wear and thermal breakdown. Group III base oils form an important part of the supply chain for many synthetic lubricants. The United States imports a substantial share of these materials from producers around the Persian Gulf. Recent disruptions affecting energy production and shipping in the Middle East have tightened the availability of some petroleum products and refining inputs.
Crude oil prices also remain elevated in mid-September. Brent crude traded near $107.82 a barrel on September 16, while West Texas Intermediate stood near $104.86. Both benchmarks remained above $100 after weeks of disruptions affecting major Middle East energy routes. Shipping through the Strait of Hormuz has also fallen sharply from normal levels, while interruptions have affected Saudi Arabia’s Red Sea export infrastructure and other regional energy operations.
Higher crude prices add pressure across petroleum markets
The Kirkland Signature products affected by the limits include popular grades used in a wide range of passenger vehicles. Costco says its synthetic motor oils provide wear protection and help control thermal breakdown. Selected Kirkland formulations also meet API SP and ILSAC GF-6A performance requirements. Mobil 1 products listed by Costco include standard, fuel-economy and high-mileage formulas, with purchase restrictions displayed on several product pages.
Costco has not publicly provided a detailed explanation for the motor oil price increase and purchase caps. Its online listings, however, now clearly show both the $57.99 Kirkland price and the two-unit seven-day restriction. Separate Mobil 1 listings continue to display five-unit membership limits. The changes come as motorists face elevated petroleum prices and constrained lubricant supplies, placing Costco’s motor oil pricing and purchase limits within a broader period of tight energy-market conditions.