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. The package includes two 5-quart bottles and is available in several common viscosity grades. Additionally, Costco has implemented a purchase restriction on certain Kirkland motor oil items. Members can buy no more than two units in a single transaction within any seven-day period.
This $57.99 price point is nearly twice the approximately $30 cost reported for the same quantity last year. Costco lists 5W-30, 5W-20, and 0W-20 Kirkland full synthetic oils at that online price. The retailer notes that prices may vary at individual warehouses compared to those on its website. Since each case contains 10 quarts, this price hike directly impacts drivers who perform routine oil changes themselves.
The purchase restrictions extend beyond Costco’s private-label products. Certain Mobil 1 full synthetic motor oils now have a cap of five units per membership. Mobil 1, an ExxonMobil brand, offers multiple formulations, including standard and high-mileage types. Affected Costco listings include six-packs of one-quart bottles across various viscosity grades, broadening restrictions to another major synthetic motor oil brand.
Restrictions on key synthetic oil brands expand at Costco
Synthetic motor oils rely on highly refined base oils combined with additives that safeguard engines under demanding conditions. Group III base oils are integral to many synthetic lubricants sold in the United States. U.S. consumers depend heavily on imported supplies, including shipments from the Persian Gulf region. Recent disruptions in Middle East energy markets have limited the availability of some petroleum products and lubricant inputs.
In mid-September, crude oil prices stayed above $100 a barrel. On September 16, Brent crude traded around $107.82, while West Texas Intermediate was near $104.86. Energy markets continued to reflect disruptions affecting production, exports, and key shipping routes in the Middle East. Traffic through the Strait of Hormuz remained below normal levels, with additional interruptions impacting Saudi Arabia’s Red Sea energy infrastructure.
Rising petroleum costs coincide with tighter lubricant supplies
The affected Kirkland products serve a broad range of passenger cars, SUVs, and light trucks. Costco states that its synthetic oils help prevent engine wear and thermal breakdown. Selected formulations meet API SP and ILSAC GF-6A standards for modern gasoline engines. The American Petroleum Institute manages API motor oil standards, while ILSAC specifications address fuel economy, engine cleanliness, and wear protection.
Costco has not issued a detailed public explanation for the increased Kirkland motor oil price or the new purchase limits. Its online listings currently reflect the $57.99 price and the two-unit weekly purchase restriction for certain products. Meanwhile, separate Mobil 1 listings still show a five-unit limit per membership on various formulations. These changes place Costco’s pricing and purchase policies for motor oil within a context of rising crude oil prices and limited lubricant supplies.