ISSAQUAH, WASHINGTON / RankWire.AI / – Costco has increased the online retail price of its Kirkland Signature full synthetic motor oil to $57.99 for a 10-quart pack. This package includes two 5-quart bottles available in several common viscosity grades. Additionally, the retailer has introduced a purchase cap on certain Kirkland motor oil products. According to current online listings, members are limited to buying no more than two units in a single transaction within a seven-day window.

The new price of $57.99 is almost double the approximately $30 cost reported for the same quantity last year. Costco now offers Kirkland 5W-30, 5W-20, and 0W-20 full synthetic oils at this elevated online rate. It’s important to note that prices at warehouse locations may vary from those displayed on the company’s website. This change primarily impacts customers purchasing larger quantities for routine vehicle upkeep, since each Kirkland package contains 10 quarts of synthetic motor oil.
Furthermore, Costco has implemented purchase limits on selected Mobil 1 synthetic motor oils. Mobil 1, a brand owned by ExxonMobil, appears in multiple Costco listings with a cap of five units per membership. These restricted products include six-packs of one-quart bottles across various viscosity grades. Some listings feature standard formulations, while others include high-mileage variants. As a result, these restrictions apply to both Costco’s private-label Kirkland oils and certain popular Mobil 1 products from a major national lubricant manufacturer.
Restrictions on motor oils extend beyond Kirkland offerings
Synthetic motor oils are produced using refined base oils combined with additives formulated to safeguard engines against heat, wear, and heavy use. Group III base oils are a key element in many synthetic lubricants sold within the United States. A significant portion of these supplies is imported by American buyers from overseas producers, including facilities located in the Persian Gulf. Recent disruptions in Middle East energy markets have led to reduced availability of certain petroleum products and have tightened supply chains for lubricants.
Crude oil prices hovered above $100 a barrel in mid-September. Brent crude traded near $107.82 on September 16, while West Texas Intermediate was close to $104.86. Ongoing supply disruptions in the Middle East continue to influence production, exports, and shipping routes, with traffic through the Strait of Hormuz remaining below normal levels. Additionally, Saudi Arabia’s Red Sea energy infrastructure faced interruptions, adding further pressure on petroleum markets and the broader network that supplies refined products and lubricants.
Rising crude oil prices coincide with shrinking lubricant supplies
The affected Kirkland motor oils cater to a wide range of passenger vehicles, SUVs, and light trucks. Costco emphasizes that its full synthetic oils are designed to protect engines from wear and thermal stress. Several products meet API SP and ILSAC GF-6A standards, which are set for modern gasoline engines. The API oversees motor oil standards in the U.S., while ILSAC specifications address fuel economy, engine cleanliness, and wear resistance. These standards are visible on numerous Kirkland synthetic oil listings.
Costco has not publicly provided detailed reasons for the recent increase in Kirkland motor oil prices or the new purchase restrictions. Currently, its website displays the $57.99 price and a limit of two units per week for certain products. Meanwhile, listings for Mobil 1 still show a five-unit limit per membership across various formulations. These changes emerge amid rising crude oil prices and tighter lubricant supplies, with Costco’s online limits defining how much members can buy during affected transactions.
