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, which includes two 5-quart bottles and comes in several common viscosity grades. The retailer now restricts members to one purchase and a maximum of two units every seven days, with these limits clearly displayed on product pages for select Kirkland Signature synthetic motor oils.
This $57.99 price marks a significant rise from the approximately $30 cost for the same quantity last year. Currently, Costco lists its 5W-30, 5W-20, and 0W-20 full synthetic two-packs at this same price online. The company notes that warehouse prices can differ depending on location. Each package contains 10 quarts of oil, making the price hike especially notable for members who do their own vehicle maintenance.
In addition to Kirkland Signature, Costco has imposed purchase restrictions on several Mobil 1 full synthetic motor oil products. Listings now show a limit of five units per membership on select six-packs with one-quart bottles, including various viscosity and high-mileage options. These restrictions extend beyond Kirkland Signature oils to include other popular synthetic brands available through the retailer.
Limits on Purchases Cover Multiple Synthetic Oil Products
Synthetic motor oils rely on highly refined base oils blended with additives that protect engines, prevent deposits, and mitigate wear and thermal breakdown. Group III base oils, a key component of many synthetics, are imported significantly into the United States from producers around the Persian Gulf. Recent disruptions in energy production and shipping in the Middle East have reduced the availability of some petroleum products and refining inputs.
Crude oil prices stay high in mid-September, with Brent crude trading near $107.82 per barrel on September 16, and West Texas Intermediate around $104.86. Both benchmarks remain above $100 after weeks of disruptions affecting major Middle East energy routes. Shipping through the Strait of Hormuz has dropped sharply, and regional operations like Saudi Arabia’s Red Sea export infrastructure have faced interruptions.
Rising crude costs exert pressure on the petroleum sector
The Kirkland Signature oils subject to purchase limits include key grades used across a variety of passenger vehicles. Costco states that its synthetic motor oils offer engine wear protection and help prevent thermal breakdown. Several formulations meet API SP and ILSAC GF-6A standards. Mobil 1 products listed by Costco include standard, fuel-economy, and high-mileage variants, with purchase restrictions shown on multiple product pages.
The company has not issued an official explanation for the price hike or the purchase restrictions. However, the online listings now explicitly show the $57.99 price for Kirkland Signature and the two-unit weekly limit. Meanwhile, Mobil 1 listings still indicate a five-unit per membership cap. These measures arrive as consumers face higher fuel costs and tighter lubricant supplies, reflecting broader energy-market constraints during this period of elevated petroleum prices.